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Difference between revisions of "Orion/ESLint"
< Orion
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== Rules == | == Rules == | ||
The following sections describe all of the rules currently available in Orion and ones that we plan to add in the future. | The following sections describe all of the rules currently available in Orion and ones that we plan to add in the future. | ||
| + | |||
| + | '''To view this table in the same order as the Orion Settings page, hover over the ''Setting Message'' column title and press the down arrow to sort.''' | ||
=== Potential Programming Problems === | === Potential Programming Problems === | ||
| Line 8: | Line 10: | ||
rules should be addressed. | rules should be addressed. | ||
| − | {| class="wikitable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" | + | {| class="wikitable sortable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" |
! width=13% | Rule | ! width=13% | Rule | ||
! width=5% | Default Severity | ! width=5% | Default Severity | ||
| Line 33: | Line 35: | ||
| ''Expected a conditional expression and instead saw an assignment.'' | | ''Expected a conditional expression and instead saw an assignment.'' | ||
| Flags assignment in an <code>if/while/do..while/for</code> condition. | | Flags assignment in an <code>if/while/do..while/for</code> condition. | ||
| − | | style="text-align:center;" | Future | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486129 Future] |
| | | | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=455371 no-console] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=455371 no-console] | ||
| − | | | + | | Ignore |
|style="text-align:center;"| 8.0 | |style="text-align:center;"| 8.0 | ||
|Discouraged console use in browser code | |Discouraged console use in browser code | ||
| Line 57: | Line 59: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Disallow control characters in regular expressions |
| ''Unexpected control character in regular expression'' | | ''Unexpected control character in regular expression'' | ||
| Control characters are special, invisible characters in the ASCII range 0-31. These characters are rarely used in JavaScript strings so a regular expression containing these characters is most likely a mistake. | | Control characters are special, invisible characters in the ASCII range 0-31. These characters are rarely used in JavaScript strings so a regular expression containing these characters is most likely a mistake. | ||
| Line 69: | Line 71: | ||
| ''debugger' statement use is discouraged.'' | | ''debugger' statement use is discouraged.'' | ||
| Warns when the <code>debugger</code> keyword is used | | Warns when the <code>debugger</code> keyword is used | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485767 ✔] |
| − | | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485767 ✔] |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428430 no-dupe-keys] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428430 no-dupe-keys] | ||
| Line 78: | Line 80: | ||
| ''Duplicate object key '{key}'.'' | | ''Duplicate object key '{key}'.'' | ||
| Flags object literals that contain the same key more than once. | | Flags object literals that contain the same key more than once. | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" |[https://bugs.eclipse.org/bugs/show_bug.cgi?id=485953 ✔] |
| | | | ||
|- | |- | ||
| Line 84: | Line 86: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Duplicate case |
| ''Duplicate case label.'' | | ''Duplicate case label.'' | ||
| A switch statements with duplicate case labels is normally an indication of a programmer error. | | A switch statements with duplicate case labels is normally an indication of a programmer error. | ||
| Line 91: | Line 93: | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=439366 no-empty-block] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=439366 no-empty-block] | ||
| − | | | + | | Ignore |
|style="text-align:center;"| 7.0 | |style="text-align:center;"| 7.0 | ||
|Undocumented empty block | |Undocumented empty block | ||
| Line 102: | Line 104: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Disallow empty character classes |
| ''Empty class.'' | | ''Empty class.'' | ||
| Empty character classes in regular expressions do not match anything and can result in code that may not work as intended. | | Empty character classes in regular expressions do not match anything and can result in code that may not work as intended. | ||
| Line 111: | Line 113: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Discourage redundant double negation |
| [http://eslint.org/docs/rules/no-extra-boolean-cast no-extra-boolean-cast] | | [http://eslint.org/docs/rules/no-extra-boolean-cast no-extra-boolean-cast] | ||
| In contexts such as an if statement's test where the result of the expression will already be coerced to a Boolean, casting to a Boolean via double negation (!!) is unnecessary. | | In contexts such as an if statement's test where the result of the expression will already be coerced to a Boolean, casting to a Boolean via double negation (!!) is unnecessary. | ||
| Line 120: | Line 122: | ||
| Warning | | Warning | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | | Discourage redundant parentheses |
| ''Gratuitous parentheses around expression.'' | | ''Gratuitous parentheses around expression.'' | ||
| This rule restricts the use of parentheses to only where they are necessary. It may be restricted to report only function expressions. | | This rule restricts the use of parentheses to only where they are necessary. It may be restricted to report only function expressions. | ||
| − | |style="text-align:center;" | | + | |style="text-align:center;" | ✔ |
| − | |style="text-align:center;" | | + | |style="text-align:center;" | ✔ |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428040 no-extra-semi] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428040 no-extra-semi] | ||
| Line 147: | Line 149: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Invalid regular expressions |
| ''Invalid flags supplied to RegExp constructor '{${0}}'.'' or the error message from calling the constructor with the regex | | ''Invalid flags supplied to RegExp constructor '{${0}}'.'' or the error message from calling the constructor with the regex | ||
| This rule validates string arguments passed to the RegExp constructor. | | This rule validates string arguments passed to the RegExp constructor. | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
|style="text-align:center;" | | |style="text-align:center;" | | ||
|style="text-align:center;" | | |style="text-align:center;" | | ||
| Line 165: | Line 158: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Disallow negated left operand of in operator |
| ''The 'in' expression's left operand is negated.'' | | ''The 'in' expression's left operand is negated.'' | ||
| Disallow negated left operand of in operator | | Disallow negated left operand of in operator | ||
| Line 174: | Line 167: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Disallow global object as function calls |
| '' '{${0}}' is not a function.'' | | '' '{${0}}' is not a function.'' | ||
| ECMAScript provides several global objects that are intended to be used as-is. Some of these objects look as if they could be constructors due their capitalization (such as Math and JSON) but will throw an error if you try to execute them as functions. | | ECMAScript provides several global objects that are intended to be used as-is. Some of these objects look as if they could be constructors due their capitalization (such as Math and JSON) but will throw an error if you try to execute them as functions. | ||
| Line 196: | Line 189: | ||
| Checks to see if a JavaScript reserved word is being used as a property key | | Checks to see if a JavaScript reserved word is being used as a property key | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485980 ✔] |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=426723 no-sparse-arrays] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=426723 no-sparse-arrays] | ||
| Line 205: | Line 198: | ||
| Flags sparse arrays with null elements like <code>var arr = [1, ,2]</code> | | Flags sparse arrays with null elements like <code>var arr = [1, ,2]</code> | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=436986 no-unreachable] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=436986 no-unreachable] | ||
| − | | | + | | Warning |
|style="text-align:center;"| 6.0 | |style="text-align:center;"| 6.0 | ||
|Unreachable code | |Unreachable code | ||
| Line 215: | Line 208: | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=425200 type-checked-consistent-return] | ||
| + | | Ignore | ||
| + | |style="text-align:center;"| 11.0 | ||
| + | |Discouraged inconsistent returns | ||
| + | | ''Inconsistent return types: (type1) (type2)'' | ||
| + | | Warns when a function returns two values with different types. | ||
| + | | style="text-align:center;" | | ||
| + | | style="text-align:center;" | | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429711 use-isnan] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429711 use-isnan] | ||
| Line 222: | Line 224: | ||
| ''Use the isNaN function to compare with NaN.'' | | ''Use the isNaN function to compare with NaN.'' | ||
| Warns when a comparison is done against NaN without using the <code>isNaN</code> function | | Warns when a comparison is done against NaN without using the <code>isNaN</code> function | ||
| − | | style="text-align:center;" | ✔ | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=470189 ✔] |
| − | | style="text-align:center;" | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485977 ✔] |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=447189 valid-typeof] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=447189 valid-typeof] | ||
| Line 240: | Line 242: | ||
you probably should not be. | you probably should not be. | ||
| − | {| class="wikitable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" | + | {| class="wikitable sortable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" |
! width=13% | Rule | ! width=13% | Rule | ||
! width=5% | Default Severity | ! width=5% | Default Severity | ||
| Line 253: | Line 255: | ||
| Warning | | Warning | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Getter and setter accessors not in pairs |
| ''Getter is not present'' or ''Setter is not present'' | | ''Getter is not present'' or ''Setter is not present'' | ||
| It's a common mistake in JavaScript to create an object with just a setter for a property but never have a corresponding getter defined for it. Without a getter, you cannot read the property, so it ends up not being used. | | It's a common mistake in JavaScript to create an object with just a setter for a property but never have a corresponding getter defined for it. Without a getter, you cannot read the property, so it ends up not being used. | ||
| Line 259: | Line 261: | ||
|style="text-align:center;" | | |style="text-align:center;" | | ||
|- | |- | ||
| − | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id= | + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=490332 check-tern-plugin] |
| − | | | + | | Warning |
| − | |style="text-align:center;" | | + | |style="text-align:center;" | 12.0 |
| − | | | + | |Missing .tern-project plugins entry for environment directive |
| − | | ''' | + | | ''To get support for the 'foo' environment, the 'bar' plugin must be started. 'bar' has not been set in the plugins entry of your .tern-project file.'' |
| − | | | + | | Warn when the an eslint-env directive specifies a library Orion provides tooling support for, but the library plugin has been disabled in the .tern-project file. |
| − | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=490332 ✔] | |
| − | | | + | | style="text-align:center;" | |
| − | | | + | |
|- | |- | ||
| − | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429722 curly] | + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429722 check-tern-project] |
| + | | Ignore | ||
| + | |style="text-align:center;" | 12.0 | ||
| + | |File should be added to .tern-project | ||
| + | | ''File should be added to .tern-project'' | ||
| + | | Warn when the current file is not part of the .tern-project file as part of the loadEagerly files property. | ||
| + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=454641 ✔] | ||
| + | | style="text-align:center;" | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=487279 curly] | ||
| Ignore | | Ignore | ||
|style="text-align:center;" | 6.0 | |style="text-align:center;" | 6.0 | ||
| Line 275: | Line 285: | ||
| ''Statements should be enclosed in braces.'' | | ''Statements should be enclosed in braces.'' | ||
| Warns when statements should be enclosed in braces, for example <code>if(something) foo();</code> | | Warns when statements should be enclosed in braces, for example <code>if(something) foo();</code> | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=454641 ✔] |
| − | | style="text-align:center;" | | + | | style="text-align:center;" | |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 eqeqeq] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 eqeqeq] | ||
| Line 288: | Line 298: | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=493019 missing-requirejs] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | 12.0 | ||
| + | |'requirejs' plugin missing in AMD environment | ||
| + | | To use AMD, the 'requirejs' plug-in needs to be running. | ||
| + | | Flags references to function calls from AMD when the Tern 'requirejs' plugin is not running | ||
| + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=493019 ✔] | ||
| + | | | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=460976 no-caller] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=460976 no-caller] | ||
| Line 295: | Line 314: | ||
| ''arguments.{callee, caller} is deprecated.'' | | ''arguments.{callee, caller} is deprecated.'' | ||
| Flags references to <code>arguments.callee</code> and <code>arguments.caller</code>. | | Flags references to <code>arguments.callee</code> and <code>arguments.caller</code>. | ||
| − | | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=459934 Future] |
| | | | ||
|- | |- | ||
| Line 301: | Line 320: | ||
| Warning | | Warning | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Unnecessary else after return |
| ''Unexpected 'else' after 'return'.'' | | ''Unexpected 'else' after 'return'.'' | ||
| If an if block contains a return statement, the else block becomes unnecessary. Its contents can be placed outside of the block. | | If an if block contains a return statement, the else block becomes unnecessary. Its contents can be placed outside of the block. | ||
| Line 310: | Line 329: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |No empty labels |
| ''Unexpected label "{${0}}"'' | | ''Unexpected label "{${0}}"'' | ||
| Labeled statements are only used in conjunction with labeled break and continue statements. ECMAScript has no goto statement. | | Labeled statements are only used in conjunction with labeled break and continue statements. ECMAScript has no goto statement. | ||
| Line 319: | Line 338: | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Disallow null comparisons |
| ''Use ‘===’ to compare with ‘null’.'' or ''Use ‘!==’ to compare with ‘null’.'' | | ''Use ‘===’ to compare with ‘null’.'' or ''Use ‘!==’ to compare with ‘null’.'' | ||
| Comparing to null without a type-checking operator (== or !=), can have unintended results as the comparison will evaluate to true when comparing to not just a null, but also an undefined value. | | Comparing to null without a type-checking operator (== or !=), can have unintended results as the comparison will evaluate to true when comparing to not just a null, but also an undefined value. | ||
| − | |style="text-align:center;" | | + | |style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485171 ✔] |
| − | |style="text-align:center;" | | + | |style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485171 ✔] |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429702 no-eval] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429702 no-eval] | ||
| Line 358: | Line 377: | ||
| ''Use the array literal notation [].'' | | ''Use the array literal notation [].'' | ||
| Flags <code>new Array()</code>. ESLint calls this rule <code>no-array-constructor</code> | | Flags <code>new Array()</code>. ESLint calls this rule <code>no-array-constructor</code> | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | ✔ |
| − | | style="text-align:center;" | | + | | style="text-align:center;" | |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429817 no-new-func] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429817 no-new-func] | ||
| Line 385: | Line 404: | ||
| ''Do not use {String, Number, Boolean, Math, JSON} as a constructor.'' | | ''Do not use {String, Number, Boolean, Math, JSON} as a constructor.'' | ||
| Flags <code>new</code> applied to any of those. | | Flags <code>new</code> applied to any of those. | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" |[https://bugs.eclipse.org/bugs/show_bug.cgi?id=485877 ✔] |
| | | | ||
|- | |- | ||
| Line 405: | Line 424: | ||
| '''{a}' is already defined.'' | | '''{a}' is already defined.'' | ||
| Usually results from having two <code>for</code> loops in the same function that share a loop variable declaration like <code>var i=...</code>. | | Usually results from having two <code>for</code> loops in the same function that share a loop variable declaration like <code>var i=...</code>. | ||
| − | | style="text-align:center;" | Future | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486123 Future] |
| | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=463490 no-self-assign] | ||
| + | | Error | ||
| + | |style="text-align:center;" | 11.0 | ||
| + | |Disallow self assignment | ||
| + | | ''Assigning to itself is pointless.'' | ||
| + | | Warns when a variable is being assigned to itself | ||
| + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486124 ✔] | ||
| + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486124 ✔] | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461850 no-self-compare] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461850 no-self-compare] | ||
| Error | | Error | ||
|style="text-align:center;"| 11.0 | |style="text-align:center;"| 11.0 | ||
| − | | | + | |Disallow self compare |
| ''Comparing to itself is potentially pointless.'' | | ''Comparing to itself is potentially pointless.'' | ||
| Comparing a variable against itself is usually an error, either an typo or refactoring error. It is confusing to the reader and may potentially introduce a runtime error. | | Comparing a variable against itself is usually an error, either an typo or refactoring error. It is confusing to the reader and may potentially introduce a runtime error. | ||
| Line 423: | Line 451: | ||
| '''{a}' is already declared in the upper scope.'' | | '''{a}' is already declared in the upper scope.'' | ||
| Flags variables that have the same name as a variable declared in an upper scope. | | Flags variables that have the same name as a variable declared in an upper scope. | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | ✔ |
| | | | ||
|- | |- | ||
| Line 432: | Line 460: | ||
| '''{a}' shadows a global member.'' | | '''{a}' shadows a global member.'' | ||
| Flags variables that have the same name as a variable declared in the global scope or specified environments. | | Flags variables that have the same name as a variable declared in the global scope or specified environments. | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | ✔ |
| | | | ||
|- | |- | ||
| Line 442: | Line 470: | ||
| Flags code that throws a literal, eg. <code>throw "a problem occurred";</code> | | Flags code that throws a literal, eg. <code>throw "a problem occurred";</code> | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 no-undef] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 no-undef] | ||
| Line 454: | Line 482: | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461852 no-undef-expression] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | 12.0 | ||
| + | |Undeclared function reference | ||
| + | | '''{member}' is undefined for '{object}' in {file}.'' | ||
| + | | Flags references to a function that is not known to be a property of an object. Will only warn if the object has known properties.</code> | ||
| + | | style="text-align:center;" | ✔ | ||
| + | | style="text-align:center;" | | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=427310 no-unused-params] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=427310 no-unused-params] | ||
| Line 467: | Line 504: | ||
| Warning | | Warning | ||
|style="text-align:center;" | 5.0 | |style="text-align:center;" | 5.0 | ||
| − | |Unused variables | + | | Unused variables |
| | | | ||
| − | *'''{a}' is | + | *'''{a}' is unread.'' |
*'''{a}' is read-only.'' | *'''{a}' is read-only.'' | ||
| + | *'''{a}' is unused.'' | ||
| + | * ''Function '{a}' is unused'' | ||
| Warns when a variable is created and not used (read) or a variable that is read-only is assigned to. | | Warns when a variable is created and not used (read) or a variable that is read-only is assigned to. | ||
| + | Warns when a function is not used. | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| style="text-align:center;" | | | style="text-align:center;" | | ||
| Line 499: | Line 539: | ||
| ''Missing radix parameter.'' | | ''Missing radix parameter.'' | ||
| Warns when parseInt() called without the 2nd parameter (radix). | | Warns when parseInt() called without the 2nd parameter (radix). | ||
| − | | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=487695 ✔] |
| − | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=487695 ✔] | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | |style="text-align:center;" | | + | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
|- | |- | ||
|} | |} | ||
| Line 516: | Line 547: | ||
These rules are not problems in any way but will warn based on certain accepted styles for coding. | These rules are not problems in any way but will warn based on certain accepted styles for coding. | ||
| − | {| class="wikitable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" | + | {| class="wikitable sortable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" |
! width=13% | Rule | ! width=13% | Rule | ||
! width=5% | Default Severity | ! width=5% | Default Severity | ||
| Line 532: | Line 563: | ||
| ''Missing documentation for function '{name}'.'' | | ''Missing documentation for function '{name}'.'' | ||
| Flags missing documentation nodes on function declarations and function expressions when they appear as object properties | | Flags missing documentation nodes on function declarations and function expressions when they appear as object properties | ||
| − | | style="text-align:center | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486125 ✔] |
| − | + | | style="text-align:center;" | | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | |style="text-align:center;" | + | |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | | | + | |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428429 missing-nls] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428429 missing-nls] | ||
| Line 551: | Line 573: | ||
| Flags String literals that are not properly NLS'd | | Flags String literals that are not properly NLS'd | ||
| style="text-align:center;" | ✔ | | style="text-align:center;" | ✔ | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486126 ✔] |
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=483010 unnecessary-nls] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=483010 unnecessary-nls] | ||
| Line 568: | Line 590: | ||
| ''Missing parentheses invoking constructor.'' | | ''Missing parentheses invoking constructor.'' | ||
| Flags <code>new Whatever</code> | | Flags <code>new Whatever</code> | ||
| − | | style="text-align:center;" | | + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486127 ✔] |
| | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=482616 no-mixed-spaces-and-tabs] | ||
| + | | Ignore | ||
| + | |style="text-align:center;"| 11.0 | ||
| + | |Mixed spaces and tabs | ||
| + | | ''Irregular whitespace not allowed.'' | ||
| + | | Invalid or irregular whitespace causes issues with ECMAScript 5 parsers and also makes code harder to debug in a similar nature to mixed tabs and spaces. | ||
| + | |style="text-align:center;" | | ||
| + | |style="text-align:center;" | | ||
|- | |- | ||
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=438095 no-jslint] | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=438095 no-jslint] | ||
| Line 577: | Line 608: | ||
| ''The 'jslint' directive is unsupported, please use eslint-env.'' | | ''The 'jslint' directive is unsupported, please use eslint-env.'' | ||
| Flags use of the /* jslint */ directive | | Flags use of the /* jslint */ directive | ||
| + | | style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=453322 Future] | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=427930 semi] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | 5.0 | ||
| + | |Missing semicolons | ||
| + | | ''Missing semicolon.'' | ||
| + | | Warns when a semicolon should be used but is not | ||
| + | | style="text-align:center;" | ✔ | ||
| + | | style="text-align:center;" | ✔ | ||
| + | |- | ||
| + | |} | ||
| + | |||
| + | === Future Implementations === | ||
| + | |||
| + | Rules that are being considered for inclusion or were implemented but removed. | ||
| + | |||
| + | {| class="wikitable sortable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;" | ||
| + | ! width=13% | Rule | ||
| + | ! width=5% | Default Severity | ||
| + | ! width=3% | Available Since | ||
| + | ! width=24% | Setting Message | ||
| + | ! width=24%| Problem Message | ||
| + | ! width=24% | Details | ||
| + | ! width=3% | Quick Fix? | ||
| + | ! width=3% | Fix All? | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428433 block-scoped-var] | ||
| + | | Error | ||
| + | |style="text-align:center;" | - | ||
| + | | | ||
| + | | '''{variable}' used outside of binding context.'' | ||
| + | | | ||
| + | Occurs when a function-scoped variable (<tt>var</tt>) is treated as if it was block scoped. | ||
| + | | | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=424204 missing-doc-items] | ||
| + | | Ignore | ||
| + | |style="text-align:center;" | - | ||
| + | | | ||
| + | | ''Missing '{a}' tag for '{b}'.'' | ||
| + | | Flags missing documentation for parameters, returns, throws, etc on function declarations and function expressions when they appear as object properties | ||
| + | | | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| no-dupe-args | ||
| + | | Error | ||
| + | |style="text-align:center;"| | ||
| + | |Duplicate parameter names | ||
| + | | ''Duplicate param '${0}''' | ||
| + | | Warns when there are duplicate function parameter names. | ||
| + | | style="text-align:center;" | Future | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486766 no-extend-native] | ||
| + | | Error | ||
| + | |style="text-align:center;" | | ||
| + | |Discouraged built-in object modification | ||
| + | | '''${0}' prototype is read only, properties should not be added.'' | ||
| + | | Warns when directly modifying the prototype of builtin objects. | ||
| + | | | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486765 no-extra-bind] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | | ||
| + | |Unnecessary 'bind()' use | ||
| + | | ''The function binding is unnecessary.'' | ||
| + | | Warns about unnecessary use of bind() | ||
| + | | | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486764 no-implicit-coercion] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | | ||
| + | |Discouraged implicit coercion use | ||
| + | | ''use `${0}` instead.'' Example: ''use `Boolean(foo)` instead.'' | ||
| + | | Warns when shorter notations are used for the type conversion, then suggest a more self-explanatory notation. | ||
| + | | style="text-align:center;" | | ||
| + | |style="text-align:center;" | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486763 no-invalid-this] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | | ||
| + | |Discouraged 'this' use | ||
| + | | ''Unexpected `this`'' | ||
| + | | This rule aims to flag usage of 'this' keywords outside of classes or class-like objects | ||
| + | | | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486761 no-lone-blocks] | ||
| + | | Warning | ||
| + | |style="text-align:center;" | | ||
| + | |Discouraged lone block use | ||
| + | | ''Block is redundant.'' or ''Nested block is redundant.'' | ||
| + | | Flags use of unnecessary and potentially confusing blocks at the top level of a script or within other blocks. | ||
| style="text-align:center;" | Future | | style="text-align:center;" | Future | ||
| | | | ||
| Line 589: | Line 718: | ||
| | | | ||
|- | |- | ||
| − | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id= | + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486760 no-native-reassign] |
| − | + | | Error | |
| + | |style="text-align:center;" | | ||
| + | |Discouraged built-in native object reassignment | ||
| + | | '''${0}' is a read-only native object.'' | ||
| + | | Flags reassignment of built-in native objects like Object and String. | ||
| + | | | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486758 no-param-reassign] | ||
| + | | Error | ||
| + | |style="text-align:center;" | | ||
| + | |Discouraged parameter reassignment | ||
| + | | ''Assignment to function parameter '${0}'.'' | ||
| + | | Flags function parameters that are reassigned | ||
| + | | style="text-align:center;" |Future | ||
| + | | | ||
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486757 no-unused-expressions] | ||
| Warning | | Warning | ||
| − | |style="text-align:center;" | | + | |style="text-align:center;" | |
| − | | | + | |Unused expressions |
| − | | '' | + | | ''Expected an assignment or function call and instead saw an expression.'' |
| − | | | + | | Flags expressions that have no effect on the running code |
| − | + | ||
| style="text-align:center;" | Future | | style="text-align:center;" | Future | ||
| + | | | ||
|- | |- | ||
| − | !style="text-align:left;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id= | + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486755 no-void] |
| Warning | | Warning | ||
| − | |style="text-align:center;" | | + | |style="text-align:center;" | |
| − | | | + | |Discouraged 'void' statement use |
| − | | '' | + | | ''Expected 'undefined' and instead saw 'void'.'' |
| − | | Warns when | + | | Warns when the void keyword is used |
| − | | style="text-align:center;" | | + | | |
| − | | style="text-align:center;" | | + | | |
| + | |- | ||
| + | !style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486754 yoda] | ||
| + | | Ignore | ||
| + | |style="text-align:center;" | | ||
| + | |Yoda conditions | ||
| + | | ''Expected literal to be on the right side of ${0}'' | ||
| + | | Warns when the literal value of a conditional expression does not come first | ||
| + | | style="text-align:center;" | Future | ||
| + | | | ||
|- | |- | ||
|} | |} | ||
| Line 653: | Line 808: | ||
[[Category:Orion]] | [[Category:Orion]] | ||
| + | [[Category:JavaScript]] | ||
Revision as of 12:42, 24 May 2016
Orion 5.0 introduced ESLint as the validator that ships with Orion. This page captures ongoing issues.
Contents
Rules
The following sections describe all of the rules currently available in Orion and ones that we plan to add in the future.
To view this table in the same order as the Orion Settings page, hover over the Setting Message column title and press the down arrow to sort.
Potential Programming Problems
These rules report about problems with your code that might have undesired or incorrect results. Warnings from these rules should be addressed.
| Rule | Default Severity | Available Since | Setting Message | Problem Message | Details | Quick Fix? | Fix All? |
|---|---|---|---|---|---|---|---|
| no-comma-dangle | Ignore | 8.0 | Trailing commas in object expressions | Trailing commas in object expressions are discouraged. | Flags trailing commas in object expressions. | ✔ | ✔ |
| no-cond-assign | Error | 8.0 | Assignments in conditional expressions | Expected a conditional expression and instead saw an assignment. | Flags assignment in an if/while/do..while/for condition.
|
Future | |
| no-console | Ignore | 8.0 | Discouraged console use in browser code | Discouraged use of console in browser-based code. | Flags the use of console in browser-based code | ||
| no-constant-condition | Error | 8.0 | Constant as conditional expression | Discouraged use of constant as a conditional expression. | Flags the use of a constant as a conditional expression | ||
| no-control-regex | Error | 11.0 | Disallow control characters in regular expressions | Unexpected control character in regular expression | Control characters are special, invisible characters in the ASCII range 0-31. These characters are rarely used in JavaScript strings so a regular expression containing these characters is most likely a mistake. | ||
| no-debugger | Warning | 6.0 | Discouraged 'debugger' statement use | debugger' statement use is discouraged. | Warns when the debugger keyword is used
|
✔ | ✔ |
| no-dupe-keys | Error | 6.0 | Duplicate object keys | Duplicate object key '{key}'. | Flags object literals that contain the same key more than once. | ✔ | |
| no-duplicate-case | Error | 11.0 | Duplicate case | Duplicate case label. | A switch statements with duplicate case labels is normally an indication of a programmer error. | ||
| no-empty-block | Ignore | 7.0 | Undocumented empty block | Empty block should be removed or commented. | Flags an empty block like if (something) { }.
|
✔ | |
| no-empty-character-class | Error | 11.0 | Disallow empty character classes | Empty class. | Empty character classes in regular expressions do not match anything and can result in code that may not work as intended. | ||
| no-extra-boolean-cast | Error | 11.0 | Discourage redundant double negation | no-extra-boolean-cast | In contexts such as an if statement's test where the result of the expression will already be coerced to a Boolean, casting to a Boolean via double negation (!!) is unnecessary. | ||
| no-extra-parens | Warning | 11.0 | Discourage redundant parentheses | Gratuitous parentheses around expression. | This rule restricts the use of parentheses to only where they are necessary. It may be restricted to report only function expressions. | ✔ | ✔ |
| no-extra-semi | Warning | 5.0 | Unnecessary semicolons | Unnecessary semicolon. | Warns when a semicolon is found where it is not needed | ✔ | ✔ |
| no-fallthrough | Error | 6.0 | Switch case fall-through | Switch case may be entered by falling through previous case. If intended, add a new comment //$FALL-THROUGH$ on the line above | Flags a fallthrough case within a switch statement, unless it is explicitly commented.
|
✔ | |
| no-invalid-regexp | Error | 11.0 | Invalid regular expressions | Invalid flags supplied to RegExp constructor '{${0}}'. or the error message from calling the constructor with the regex | This rule validates string arguments passed to the RegExp constructor. | ||
| no-negated-in-lhs | Error | 11.0 | Disallow negated left operand of in operator | The 'in' expression's left operand is negated. | Disallow negated left operand of in operator | ||
| no-obj-calls | Error | 11.0 | Disallow global object as function calls | '{${0}}' is not a function. | ECMAScript provides several global objects that are intended to be used as-is. Some of these objects look as if they could be constructors due their capitalization (such as Math and JSON) but will throw an error if you try to execute them as functions. | ||
| no-regex-spaces | Error | 8.0 | Multiple spaces in regular expressions | Avoid using multiple spaces in regular expressions. Use ' {${0}}' instead. | Flags regular expressions that have two or more subsequent spaces. | ||
| no-reserved-keys | Error | 8.0 | Reserved words used as property keys | Reserved words should not be used as property keys. | Checks to see if a JavaScript reserved word is being used as a property key | ✔ | ✔ |
| no-sparse-arrays | Warning | 8.0 | Sparse array declarations | Sparse array declarations should be avoided. | Flags sparse arrays with null elements like var arr = [1, ,2]
|
✔ | |
| no-unreachable | Warning | 6.0 | Unreachable code | Unreachable code. | Flags statements that occur after a return, throw, etc.
|
✔ | |
| type-checked-consistent-return | Ignore | 11.0 | Discouraged inconsistent returns | Inconsistent return types: (type1) (type2) | Warns when a function returns two values with different types. | ||
| use-isnan | Error | 6.0 | NaN not compared with isNaN() | Use the isNaN function to compare with NaN. | Warns when a comparison is done against NaN without using the isNaN function
|
✔ | ✔ |
| valid-typeof | Error | 7.0 | Invalid 'typeof' comparison | Invalid typeof comparison. | Warns when a typeof comparison uses an invalid type. |
Best Practices
These rules are not necessarily problem with your code, but are warnings that you might be doing something you probably should not be.
| Rule | Default Severity | Available Since | Setting Message | Problem Message | Details | Quick Fix? | Fix All? |
|---|---|---|---|---|---|---|---|
| accessor-pairs | Warning | 11.0 | Getter and setter accessors not in pairs | Getter is not present or Setter is not present | It's a common mistake in JavaScript to create an object with just a setter for a property but never have a corresponding getter defined for it. Without a getter, you cannot read the property, so it ends up not being used. | ||
| check-tern-plugin | Warning | 12.0 | Missing .tern-project plugins entry for environment directive | To get support for the 'foo' environment, the 'bar' plugin must be started. 'bar' has not been set in the plugins entry of your .tern-project file. | Warn when the an eslint-env directive specifies a library Orion provides tooling support for, but the library plugin has been disabled in the .tern-project file. | ✔ | |
| check-tern-project | Ignore | 12.0 | File should be added to .tern-project | File should be added to .tern-project | Warn when the current file is not part of the .tern-project file as part of the loadEagerly files property. | ✔ | |
| curly | Ignore | 6.0 | Statements not enclosed in braces | Statements should be enclosed in braces. | Warns when statements should be enclosed in braces, for example if(something) foo();
|
✔ | |
| eqeqeq | Warning | 5.0 | Discouraged '==' use |
|
Warns when == or != is used
|
✔ | ✔ |
| missing-requirejs | Warning | 12.0 | 'requirejs' plugin missing in AMD environment | To use AMD, the 'requirejs' plug-in needs to be running. | Flags references to function calls from AMD when the Tern 'requirejs' plugin is not running | ✔ | |
| no-caller | Error | 9.0 | Discouraged 'arguments.caller' or 'arguments.callee' use | arguments.{callee, caller} is deprecated. | Flags references to arguments.callee and arguments.caller.
|
Future | |
| no-else-return | Warning | 11.0 | Unnecessary else after return | Unexpected 'else' after 'return'. | If an if block contains a return statement, the else block becomes unnecessary. Its contents can be placed outside of the block. | ||
| no-empty-label | Error | 11.0 | No empty labels | Unexpected label "{${0}}" | Labeled statements are only used in conjunction with labeled break and continue statements. ECMAScript has no goto statement. | ||
| no-eq-null | Error | 11.0 | Disallow null comparisons | Use ‘===’ to compare with ‘null’. or Use ‘!==’ to compare with ‘null’. | Comparing to null without a type-checking operator (== or !=), can have unintended results as the comparison will evaluate to true when comparing to not just a null, but also an undefined value. | ✔ | ✔ |
| no-eval | Ignore | 6.0 | Discouraged 'eval()' use | 'eval' function calls are discouraged. | Warns when the eval() function is used
|
||
| no-implied-eval | Ignore | 6.0 | Discouraged implied 'eval()' use | Implicit 'eval' function calls are discouraged. | Flags calls to the string-argument form of setTimeout and setInterval, which implicitly perform eval. This rule logic was merged to be part of the no-eval rule.
|
||
| no-iterator | Error | 8.0 | Discouraged __iterator__ property use | Discouraged __iterator__ property use. | Flags use of __iterator__ as an identifier name or property key.
|
||
| no-new-array | Warning | 6.0 | Discouraged 'new Array()' | Use the array literal notation []. | Flags new Array(). ESLint calls this rule no-array-constructor
|
✔ | |
| no-new-func | Warning | 6.0 | Discouraged 'new Function()' | The Function constructor is eval. | Flags new Function().
|
||
| no-new-object | Warning | 6.0 | Discouraged 'new Object()' | Use the object literal notation {}. | Flags new Object().
|
||
| no-new-wrappers | Warning | 6.0 | Discouraged wrapper objects | Do not use {String, Number, Boolean, Math, JSON} as a constructor. | Flags new applied to any of those.
|
✔ | |
| no-proto | Error | 9.0 | Discouraged __proto__ property use |
|
Flags use of the property __proto__ as object keys or in assignments
|
||
| no-redeclare | Warning | 5.0 | Variable re-declarations | '{a}' is already defined. | Usually results from having two for loops in the same function that share a loop variable declaration like var i=....
|
Future | |
| no-self-assign | Error | 11.0 | Disallow self assignment | Assigning to itself is pointless. | Warns when a variable is being assigned to itself | ✔ | ✔ |
| no-self-compare | Error | 11.0 | Disallow self compare | Comparing to itself is potentially pointless. | Comparing a variable against itself is usually an error, either an typo or refactoring error. It is confusing to the reader and may potentially introduce a runtime error. | ||
| no-shadow | Warning | 8.0 | Variable shadowing | '{a}' is already declared in the upper scope. | Flags variables that have the same name as a variable declared in an upper scope. | ✔ | |
| no-shadow-global | Warning | 9.0 | Global shadowing | '{a}' shadows a global member. | Flags variables that have the same name as a variable declared in the global scope or specified environments. | ✔ | |
| no-throw-literal | Warning | 9.0 | Literal used in 'throw' | Throw an Error instead. | Flags code that throws a literal, eg. throw "a problem occurred";
|
✔ | |
| no-undef | Error | 5.0 | Undeclared global reference | '{variable}' is not defined. |
|
✔ | |
| no-undef-expression | Warning | 12.0 | Undeclared function reference | '{member}' is undefined for '{object}' in {file}. | Flags references to a function that is not known to be a property of an object. Will only warn if the object has known properties.</code> | ✔ | |
| no-unused-params | Warning | 6.0 | Unused parameters | Parameter '{param}' is not used. | Flags parameters in function declarations / expressions if they are not being used | ✔ | |
| no-unused-vars | Warning | 5.0 | Unused variables |
|
Warns when a variable is created and not used (read) or a variable that is read-only is assigned to.
Warns when a function is not used. |
✔ | |
| no-use-before-define | Warning | 5.0 | Member used before definition | '{a}' was used before it was defined. | Warns when a variable or function is used before it is defined | ||
| no-with | Warning | 9.0 | Discouraged 'with' statement use | Expected an identifier and instead saw 'with'. | Treated as fatal parse error in JSLint. | ||
| radix | Warning | 8.0 | Missing radix parameter to parseInt() | Missing radix parameter. | Warns when parseInt() called without the 2nd parameter (radix). | ✔ | ✔ |
Code Style
These rules are not problems in any way but will warn based on certain accepted styles for coding.
| Rule | Default Severity | Available Since | Setting Message | Problem Message | Details | Quick Fix? | Fix All? |
|---|---|---|---|---|---|---|---|
| missing-doc | Ignore | 5.0 | Missing JSDoc | Missing documentation for function '{name}'. | Flags missing documentation nodes on function declarations and function expressions when they appear as object properties | ✔ | |
| missing-nls | Ignore | 9.0 | Non-externalized string literals (missing $NON-NLS$ tag) | Non-externalized string literal '{a}'. | Flags String literals that are not properly NLS'd | ✔ | ✔ |
| unnecessary-nls | Ignore | 11.0 | Unnecessary $NON-NLS$ tags | Unnecessary $NON-NLS$ tag. | Flags $NON-NLS$ comments that are not needed to exclude a string literal | ✔ | ✔ |
| new-parens | Error | 6.0 | Missing parentheses in constructor call | Missing parentheses invoking constructor. | Flags new Whatever
|
✔ | |
| no-mixed-spaces-and-tabs | Ignore | 11.0 | Mixed spaces and tabs | Irregular whitespace not allowed. | Invalid or irregular whitespace causes issues with ECMAScript 5 parsers and also makes code harder to debug in a similar nature to mixed tabs and spaces. | ||
| no-jslint | Warning | 7.0 | Unsupported environment directive | The 'jslint' directive is unsupported, please use eslint-env. | Flags use of the /* jslint */ directive | Future | |
| semi | Warning | 5.0 | Missing semicolons | Missing semicolon. | Warns when a semicolon should be used but is not | ✔ | ✔ |
Future Implementations
Rules that are being considered for inclusion or were implemented but removed.
| Rule | Default Severity | Available Since | Setting Message | Problem Message | Details | Quick Fix? | Fix All? |
|---|---|---|---|---|---|---|---|
| block-scoped-var | Error | - | '{variable}' used outside of binding context. |
Occurs when a function-scoped variable (var) is treated as if it was block scoped. |
|||
| missing-doc-items | Ignore | - | Missing '{a}' tag for '{b}'. | Flags missing documentation for parameters, returns, throws, etc on function declarations and function expressions when they appear as object properties | |||
| no-dupe-args | Error | Duplicate parameter names | Duplicate param '${0}' | Warns when there are duplicate function parameter names. | Future | ||
| no-extend-native | Error | Discouraged built-in object modification | '${0}' prototype is read only, properties should not be added. | Warns when directly modifying the prototype of builtin objects. | |||
| no-extra-bind | Warning | Unnecessary 'bind()' use | The function binding is unnecessary. | Warns about unnecessary use of bind() | |||
| no-implicit-coercion | Warning | Discouraged implicit coercion use | use `${0}` instead. Example: use `Boolean(foo)` instead. | Warns when shorter notations are used for the type conversion, then suggest a more self-explanatory notation. | |||
| no-invalid-this | Warning | Discouraged 'this' use | Unexpected `this` | This rule aims to flag usage of 'this' keywords outside of classes or class-like objects | |||
| no-lone-blocks | Warning | Discouraged lone block use | Block is redundant. or Nested block is redundant. | Flags use of unnecessary and potentially confusing blocks at the top level of a script or within other blocks. | Future | ||
| no-mixed-returns | Error | - | Mixed return types should be avoided. | Flags functions that return more than one kind of item, for example returning String and Object | |||
| no-native-reassign | Error | Discouraged built-in native object reassignment | '${0}' is a read-only native object. | Flags reassignment of built-in native objects like Object and String. | |||
| no-param-reassign | Error | Discouraged parameter reassignment | Assignment to function parameter '${0}'. | Flags function parameters that are reassigned | Future | ||
| no-unused-expressions | Warning | Unused expressions | Expected an assignment or function call and instead saw an expression. | Flags expressions that have no effect on the running code | Future | ||
| no-void | Warning | Discouraged 'void' statement use | Expected 'undefined' and instead saw 'void'. | Warns when the void keyword is used | |||
| yoda | Ignore | Yoda conditions | Expected literal to be on the right side of ${0} | Warns when the literal value of a conditional expression does not come first | Future |
Implementing a new rule
This section explains how to implement a new linting rule. For brevity, all paths are given relative to bundles/org.eclipse.orion.client.javascript/web/ in the client repo.
First, create the tests and rule:
- Create a new describe("{rule-name}") block in: /js-tests/javascript/eslintRuleTests.js. Add several tests to it.
- Run the JS bundle tests and ensure that your new tests fail.
- Implement the actual logic for your rule in /eslint/lib/load-rules-async.js.
- Run the tests again. This time they should all pass.
To get your rule running in the Orion product's validator, there are additional steps:
- Create strings for the validation message(s) generated by your rule in /javascript/nls/root/problems.js.
- Create a short string describing what your rule does in /javascript/nls/root/messages.js.
- Add an entry to the orion.core.setting declaration in /javascript/plugins/javascriptPlugin.js. This allows your rule to be configured from the JS validator settings page. Make sure it references the same nameKey used in messages.js.
- Add a config entry for your rule to /javascript/ruleData.js.
- Add your rule to the #updated() handler in /javascript/validator.js.
Reload the JS plugin, and your rule should now be configurable from the Settings page, and properly set up for translation too.
Tests
- Every rule needs extensive unit tests.
- Unit tests should use Mocha.
Running the tests
- To run the ESLint tests as part of the main JavaScript tests suite load {orion-server-url}/javascript/js-tests/JsMochaSuite.html in your web browser.
- To run just the ESLint rule tests, load {orion-server-url}/js-tests/javascript/JsMochaSuite.html?grep=ESLint%20Rule%20Tests in your browser.
- To run just the ESLint core tests, load {orion-server-url}/js-tests/javascript/JsMochaSuite.html?grep=ESLint%20Core%20Tests in your browser.
- To run only a subset of the tests, add ?grep=ESLint%20Rule%20Tests onto the test page URL.
See Mocha usage options for more options.
User interface
-
Should we have a UI for configuring what rules are active?bug 424268. - Should we try to support
.eslintrc? This would be an ideal project-scope setting, and is being tracked in bug 461228. -
Should we try to honor equivalent JSLint/JSHint flags when possible? For example/*jslint eqeqeq:false */could disable the eqeqeq rule on a per-file basis.- ESLint now has its own syntax for this:
/*eslint ..*/, which we are using instead.
- ESLint now has its own syntax for this:
i18n
We need to support i18n. Pre-req is bug 422278 (orion.edit.validator support for i18n).