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Difference between revisions of "Orion/ESLint"

(Add bug links for curly fixes)
(Potential Programming Problems: Fix bad formatting on no-irregular-whitespace rule)
 
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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 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;" |
|
+
|style="text-align:center;" | ✔
 
|-
 
|-
 
!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]
| Warning
+
| 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 49: Line 51:
 
|style="text-align:center;"| 8.0
 
|style="text-align:center;"| 8.0
 
|Constant as conditional expression
 
|Constant as conditional expression
| ''Discouraged use of constant as a conditional expression.''
+
| ''...'' is constant.
 
| Flags the use of a constant as a conditional expression
 
| Flags the use of a constant as a conditional expression
 +
|
 +
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=455680 no-const-assign]
 +
| Error
 +
|style="text-align:center;"| 13.0
 +
| Disallow modifying variables that are declared using const
 +
| ''Discouraged use of constant as a conditional expression.''
 +
| Flags the assignment to a constant variable
 
|
 
|
 
|
 
|
Line 91: Line 102:
 
|-
 
|-
 
!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]
| Warning
+
| Ignore
 
|style="text-align:center;"| 7.0
 
|style="text-align:center;"| 7.0
 
|Undocumented empty block
 
|Undocumented empty block
Line 112: Line 123:
 
|style="text-align:center;"| 11.0
 
|style="text-align:center;"| 11.0
 
|Discourage redundant double negation
 
|Discourage redundant double negation
| [http://eslint.org/docs/rules/no-extra-boolean-cast no-extra-boolean-cast]
+
| Redundant double negation in ...
 
| 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.
 
|style="text-align:center;" |
 
|style="text-align:center;" |
Line 123: Line 134:
 
| ''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 153: Line 164:
 
|style="text-align:center;" |
 
|style="text-align:center;" |
 
|-
 
|-
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=482616 no-irregular-whitespace]
+
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=482616 no-irregular-whitespace]  
 
| Ignore
 
| Ignore
 
|style="text-align:center;"| 11.0
 
|style="text-align:center;"| 11.0
|Mixed spaces and tabs
+
| Report irregular whitespace
| ''Irregular whitespace not allowed.''
+
| '''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.
+
| This rule validates all whitespaces
 
|style="text-align:center;" |
 
|style="text-align:center;" |
 
|style="text-align:center;" |
 
|style="text-align:center;" |
Line 190: Line 201:
 
|-
 
|-
 
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=455354 no-reserved-keys]
 
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=455354 no-reserved-keys]
| Error
+
| Ignore
 
|style="text-align:center;"| 8.0
 
|style="text-align:center;"| 8.0
 
|Reserved words used as property keys
 
|Reserved words used as property keys
Line 205: Line 216:
 
| 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;" | Future
+
| 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]
| Error
+
| Warning
 
|style="text-align:center;"| 6.0
 
|style="text-align:center;"| 6.0
 
|Unreachable code
 
|Unreachable code
Line 215: Line 226:
 
| 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 259: Line 279:
 
|style="text-align:center;" |
 
|style="text-align:center;" |
 
|-
 
|-
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428433 block-scoped-var]
+
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=490332 check-tern-plugin]
| Error
+
| Warning
|style="text-align:center;" | -
+
|style="text-align:center;" | 12.0
|
+
|Missing .tern-project plugins entry for environment directive
| '''{variable}' used outside of binding context.''
+
| ''To work in the 'foo' environment, the 'bar' plugin must be running.''
|
+
| 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.
Occurs when a function-scoped variable (<tt>var</tt>) is treated as if it was block scoped.
+
| 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=487279 curly]
 
| Ignore
 
| Ignore
 
|style="text-align:center;" | 6.0
 
|style="text-align:center;" | 6.0
Line 275: Line 294:
 
| ''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;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=454641 Future]
+
| style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=454641 ]
| style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=454641 Future]
+
| 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 307:
 
| 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 323:
 
| ''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 304: Line 332:
 
| ''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.
|style="text-align:center;" |
+
| style="text-align:center;" |
 
|style="text-align:center;" |
 
|style="text-align:center;" |
 
|-
 
|-
Line 324: Line 352:
 
|style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485171 ✔]
 
|style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485171 ✔]
 
|style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=485171 ✔]
 
|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=486766 no-extend-native]
 +
| Error
 +
|style="text-align:center;"| 13.0
 +
| Disallow extending of native objects
 +
| '..... prototype is read only, properties should not be added.'
 +
| Disallows directly modifying the prototype of builtin objects.
 +
|style="text-align:center;" |
 +
|style="text-align:center;" |
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486765 no-extra-bind]
 +
| Warning
 +
|style="text-align:center;" | 13.0
 +
|Unnecessary 'bind()' use
 +
| ''The function binding is unnecessary.''
 +
| Warns about unnecessary use of bind()
 +
|style="text-align:center;" | ✔
 +
|style="text-align:center;" | ✔
 
|-
 
|-
 
!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 332: Line 378:
 
| Warns when the <code>eval()</code> function is used
 
| Warns when the <code>eval()</code> function is used
 
|
 
|
 +
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486764 no-implicit-coercion]
 +
| Warning
 +
|style="text-align:center;" | 13.0
 +
|Disallow the type conversion with shorter notations.
 +
| ''use `Boolean(..)` instead.'', ''use `...indexOf(".") !== -1` instead.'', ''use `Number(..)` instead.'', ''use `String(foo)` instead.''
 +
| This rule is aimed to flag shorter notations for the type conversion, then suggest a more self-explanatory notation.
 +
|
 
|
 
|
 
|-
 
|-
Line 340: Line 395:
 
| ''Implicit 'eval' function calls are discouraged.''
 
| ''Implicit 'eval' function calls are discouraged.''
 
| Flags calls to the string-argument form of <code>setTimeout</code> and <code>setInterval</code>, which implicitly perform <code>eval</code>. This rule logic was merged to be part of the <b>no-eval</b> rule.
 
| Flags calls to the string-argument form of <code>setTimeout</code> and <code>setInterval</code>, which implicitly perform <code>eval</code>. This rule logic was merged to be part of the <b>no-eval</b> rule.
 +
|
 +
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486763 no-invalid-this]
 +
| Warning
 +
|style="text-align:center;" | 13.0
 +
|Discouraged 'this' use outside of classes or class-like objects
 +
| ''Unexpected 'this'''
 +
| This rule aims to flag usage of 'this' keywords outside of classes or class-like objects
 
|  
 
|  
 
|
 
|
Line 349: Line 413:
 
| ''Discouraged __iterator__ property use.''
 
| ''Discouraged __iterator__ property use.''
 
| Flags use of <code>__iterator__</code> as an identifier name or property key.
 
| Flags use of <code>__iterator__</code> as an identifier name or property key.
 +
|
 +
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486761 no-lone-blocks]
 +
| Ignore
 +
|style="text-align:center;" | 13.0
 +
|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;" |
 +
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486760 no-native-reassign]
 +
| Error
 +
|style="text-align:center;" | 13.0
 +
| Disallow reassignment of native objects
 +
| ''... is a read-only native object.''
 +
| This rule flags modifications to read-only global variables
 
|  
 
|  
 
|
 
|
Line 386: Line 468:
 
| Flags <code>new</code> applied to any of those.
 
| Flags <code>new</code> applied to any of those.
 
| style="text-align:center;" |[https://bugs.eclipse.org/bugs/show_bug.cgi?id=485877 ✔]
 
| style="text-align:center;" |[https://bugs.eclipse.org/bugs/show_bug.cgi?id=485877 ✔]
 +
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486758 no-param-reassign]
 +
| Ignore
 +
|style="text-align:center;" | 13.0
 +
| Disallow Reassignment of Function Parameters
 +
|
 +
* ''Assignment to function parameter 'bar'.''
 +
* ''Assignment to property of function parameter 'bar'.''
 +
| Report parameter reassignment inside functions. Can also report reassignment of parameter's properties.
 +
|
 
|
 
|
 
|-
 
|-
Line 405: Line 498:
 
| '''{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;" |
 
|
 
|
 +
|-
 +
!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
 +
| '''{a}' is assigned to itself.''
 +
| 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]
Line 442: Line 544:
 
| 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;" | Future
+
| 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 556:
 
| 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.
 +
| style="text-align:center;" | ✔
 +
| style="text-align:center;" |
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461852 no-undef-init]
 +
| Warning
 +
|style="text-align:center;" | 9.0
 +
| Undeclared function reference
 +
| ''Avoid explicitly initializing variables to 'undefined'.''
 +
| Avoid initializing variables to undefined.
 +
| style="text-align:center;" | ✔
 +
| style="text-align:center;" | ✔
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486757 no-unused-expressions]
 +
| Ignore
 +
|style="text-align:center;" | 13.0
 +
| 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;" | ✔
 +
| 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 596:
 
| Warning
 
| Warning
 
|style="text-align:center;" | 5.0
 
|style="text-align:center;" | 5.0
|Unused variables
+
| Unused variables
 
|  
 
|  
*'''{a}' is not read.''
+
*'''{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 480: Line 612:
 
|Member used before definition
 
|Member used before definition
 
| '''{a}' was used before it was defined.''
 
| '''{a}' was used before it was defined.''
| Warns when a variable or function is used before it is defined
+
| Warns when a variable, function or class is used before it is defined
 
|  
 
|  
 
|
 
|
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486755 no-void]
 +
| Ignore
 +
|style="text-align:center;"| 13.0
 +
| Disallow use of the void operator.
 +
| Expected 'undefined' and instead saw 'void'.
 +
| Discourage the usage of the void operator.
 +
|style="text-align:center;" |
 +
|style="text-align:center;" |
 
|-
 
|-
 
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461854 no-with]
 
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461854 no-with]
Line 499: Line 640:
 
| ''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:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=463490 no-self-assign]
+
!style="text-align:left;"| unknown-require
| Error
+
| Warning
|style="text-align:center;" | 11.0
+
|style="text-align:center;" | 12.0
|Disallow self assignment
+
| Validation of the tern settings
| ''Assigning to itself is pointless.''
+
| ''This library could not be found, type information for it will be incomplete.''
| Warns when a variable is being assigned to itself
+
| Validation of the tern settings for libraries.
| style="text-align:center;" | Future
+
| style="text-align:center;" | ✔
| style="text-align:center;" | Future
+
| style="text-align:center;" |
 +
|-
 +
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486754 yoda]
 +
| Ignore
 +
|style="text-align:center;" | 13.0
 +
| Require or disallow Yoda Conditions
 +
|
 +
* ''Expected literal to be on the right side of ...''
 +
* ''Expected literal to be on the left side of ...''
 +
| Enforce consistent style of conditions which compare a variable to a literal value.
 +
|
 +
|
 
|-
 
|-
 
|}
 
|}
Line 532: Line 684:
 
| ''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;" | Future
+
| style="text-align:center;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=486125 ✔]
| style="text-align:center;" | Future
+
| style="text-align:center;" |  
|-
+
!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;"| [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 694:
 
| 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;" | Future
+
| 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]
+
| Ignore
+
|style="text-align:center;" | 11.0
+
|Unnecessary $NON-NLS$ tags
+
| ''Unnecessary $NON-NLS$ tag.''
+
| Flags $NON-NLS$ comments that are not needed to exclude a string literal
+
| style="text-align:center;" | ✔
+
| style="text-align:center;" | ✔
+
 
|-
 
|-
 
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429801 new-parens]
 
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429801 new-parens]
Line 568: Line 702:
 
| ''Missing parentheses invoking constructor.''
 
| ''Missing parentheses invoking constructor.''
 
| Flags <code>new Whatever</code>  
 
| Flags <code>new Whatever</code>  
| style="text-align:center;" | Future
+
| 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 720:
 
| ''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;" | Future
+
| 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=425200 no-mixed-returns]
+
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=500436 no-trailing-spaces]
| Error
+
| Ignore
|style="text-align:center;" | -
+
|style="text-align:center;" | 13.0
|
+
| Unsupported environment directive
| ''Mixed return types should be avoided.''
+
| ''Trailing spaces not allowed.''
| Flags functions that return more than one kind of item, for example returning String and Object
+
| Flags any trailing spaces
|  
+
| style="text-align:center;" | ✔
|
+
| style="text-align:center;" | ✔
 
|-
 
|-
!style="text-align:left;"| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=461852 no-undef-init]
+
!style="text-align:left;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=482619 quotes]
Moved to best practices
+
| Ignore
| Warning
+
|style="text-align:center;" | 13.0
|style="text-align:center;" | 9.0
+
| Validate which quotes should be used (either single, double or backtick (es6 only))
|Explicitly initializing variables to undefined
+
| ''Strings must use doublequote.'', ''Strings must use singlequote.'', ''Strings must use backtick.''
| ''Avoid explicitly initializing variables to 'undefined'.''
+
| Warns when a quote is not the expected one
| Warns when an explicit assignment to undefined is done, for example <code>var foo = undefined;</code>
+
| style="text-align:center;" |
| style="text-align:center;" | Future
+
| style="text-align:center;" |
| style="text-align:center;" | Future
+
 
|-
 
|-
 
!style="text-align:left;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=427930 semi]
 
!style="text-align:left;" | [https://bugs.eclipse.org/bugs/show_bug.cgi?id=427930 semi]
Line 607: Line 749:
 
| 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=483010 unnecessary-nls]
 +
| Ignore
 +
|style="text-align:center;" | 11.0
 +
|Unnecessary $NON-NLS$ tags
 +
| ''Unnecessary $NON-NLS$ tag.''
 +
| Flags $NON-NLS$ comments that are not needed to exclude a string literal
 +
| 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
 +
|
 +
|
 
|-
 
|-
 
|}
 
|}
Line 653: Line 839:
  
 
[[Category:Orion]]
 
[[Category:Orion]]
 +
[[Category:JavaScript]]

Latest revision as of 17:38, 8 December 2016

Orion 5.0 introduced ESLint as the validator that ships with Orion. This page captures ongoing issues.

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.
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 ... is constant. Flags the use of a constant as a conditional expression
no-const-assign Error 13.0 Disallow modifying variables that are declared using const Discouraged use of constant as a conditional expression. Flags the assignment to a constant variable
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 Redundant double negation in ... 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 '{${0}}'. or the error message from calling the constructor with the regex This rule validates string arguments passed to the RegExp constructor.
no-irregular-whitespace Ignore 11.0 Report irregular whitespace 'Irregular whitespace not allowed This rule validates all whitespaces
no-negated-in-lhs Error 11.0 Disallow negated left operand of in operator The 'in' expression's left operand is negated. Disallow negated left operand of in operator
no-obj-calls Error 11.0 Disallow global object as function calls '{${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 Ignore 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 work in the 'foo' environment, the 'bar' plugin must be running. 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.
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
  • Expected '===' and saw '=='.
  • Expected '!==' and saw '!='.
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-extend-native Error 13.0 Disallow extending of native objects '..... prototype is read only, properties should not be added.' Disallows directly modifying the prototype of builtin objects.
no-extra-bind Warning 13.0 Unnecessary 'bind()' use The function binding is unnecessary. Warns about unnecessary use of bind()
no-eval Ignore 6.0 Discouraged 'eval()' use 'eval' function calls are discouraged. Warns when the eval() function is used
no-implicit-coercion Warning 13.0 Disallow the type conversion with shorter notations. use `Boolean(..)` instead., use `...indexOf(".") !== -1` instead., use `Number(..)` instead., use `String(foo)` instead. This rule is aimed to flag shorter notations for the type conversion, then suggest a more self-explanatory notation.
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-invalid-this Warning 13.0 Discouraged 'this' use outside of classes or class-like objects Unexpected 'this' This rule aims to flag usage of 'this' keywords outside of classes or class-like objects
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-lone-blocks Ignore 13.0 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.
no-native-reassign Error 13.0 Disallow reassignment of native objects ... is a read-only native object. This rule flags modifications to read-only global variables
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-param-reassign Ignore 13.0 Disallow Reassignment of Function Parameters
  • Assignment to function parameter 'bar'.
  • Assignment to property of function parameter 'bar'.
Report parameter reassignment inside functions. Can also report reassignment of parameter's properties.
no-proto Error 9.0 Discouraged __proto__ property use
  • Reserved name '__proto__' should not be assigned.
  • Reserved name '__proto__' should not be used as a key.
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=....
no-self-assign Error 11.0 Disallow self assignment '{a}' is assigned to itself. 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.
  • Flags references to a global variable that is not listed in a /*global*/ or /*globals*/ block.
  • Predefined environments (eg. node, browser, amd) can be set in a /*eslint-env*/ block.
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.
no-undef-init Warning 9.0 Undeclared function reference Avoid explicitly initializing variables to 'undefined'. Avoid initializing variables to undefined.
no-unused-expressions Ignore 13.0 Unused expressions Expected an assignment or function call and instead saw an expression. Flags expressions that have no effect on the running 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
  • '{a}' is unread.
  • '{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 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, function or class is used before it is defined
no-void Ignore 13.0 Disallow use of the void operator. Expected 'undefined' and instead saw 'void'. Discourage the usage of the void operator.
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).
unknown-require Warning 12.0 Validation of the tern settings This library could not be found, type information for it will be incomplete. Validation of the tern settings for libraries.
yoda Ignore 13.0 Require or disallow Yoda Conditions
  • Expected literal to be on the right side of ...
  • Expected literal to be on the left side of ...
Enforce consistent style of conditions which compare a variable to a literal value.

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
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
no-trailing-spaces Ignore 13.0 Unsupported environment directive Trailing spaces not allowed. Flags any trailing spaces
quotes Ignore 13.0 Validate which quotes should be used (either single, double or backtick (es6 only)) Strings must use doublequote., Strings must use singlequote., Strings must use backtick. Warns when a quote is not the expected one
semi Warning 5.0 Missing semicolons Missing semicolon. Warns when a semicolon should be used but is not
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

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

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:

  1. Create a new describe("{rule-name}") block in: /js-tests/javascript/eslintRuleTests.js. Add several tests to it.
  2. Run the JS bundle tests and ensure that your new tests fail.
  3. Implement the actual logic for your rule in /eslint/lib/load-rules-async.js.
  4. 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:

  1. Create strings for the validation message(s) generated by your rule in /javascript/nls/root/problems.js.
  2. Create a short string describing what your rule does in /javascript/nls/root/messages.js.
  3. 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.
  4. Add a config entry for your rule to /javascript/ruleData.js.
  5. 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.

i18n

We need to support i18n. Pre-req is bug 422278 (orion.edit.validator support for i18n).

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