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Orion 5.0 will replace our current JSLint validator with [https://github.com/nzakas/eslint/ ESLint]. This page captures ongoing issues.
+
Orion 5.0 moved to [https://github.com/nzakas/eslint/ ESLint] as the validator that ships with Orion. This page captures ongoing issues.
  
== Rule parity ==  
+
== Rules ==  
Here's a table showing the equivalent validation rules in JSLint and ESLint. Rules that JSLint does not support are marked as Unsupported.  
+
The following table describes all of the rules currently available in Orion and ones that we plan to add in the future.
 +
 
 +
Rules that are currently available are <del>struck out</del>.
  
 
{| class="wikitable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;"
 
{| class="wikitable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;"
! style="background:#efefef;" | ESLint rule
+
! style="background:#efefef;" width=5% | Rule
! style="background:#efefef;" | JSLint option
+
! style="background:#efefef;" width=5% | Default Severity
! style="background:#efefef;" | JSLint message
+
! style="background:#efefef;" width=5% | Available Since
! style="background:#efefef;" | Details
+
! style="background:#efefef;" width=40%| Problem Message
 +
! style="background:#efefef;" width=40% | Details
 
|-
 
|-
  
!| block-scoped-var
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428433 block-scoped-var]
| Always on
+
| Error
 +
| -
 
| '''{variable}' is already defined.''
 
| '''{variable}' is already defined.''
 
|
 
|
Line 20: Line 24:
  
 
!| brace-style
 
!| brace-style
| Unsupported
+
| Ignore
|  
+
| -
|  
+
| &nbsp;
 +
| &nbsp;
 
|-
 
|-
  
 
!| camelcase
 
!| camelcase
| Unsupported
+
| Ignore
|  
+
| -
|  
+
| &nbsp;
 +
| &nbsp;
 
|-
 
|-
  
 
!| complexity
 
!| complexity
| Unsupported
+
| Ignore
|   
+
-
|  
+
| &nbsp;
 +
| &nbsp;
 
|-
 
|-
  
 
!| consistent-this
 
!| consistent-this
| Unsupported
+
| Ignore
|   
+
-
|  
+
| &nbsp;
 +
| &nbsp;
 
|-
 
|-
  
!| curly
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=429722 curly]</del>
| Always on
+
| Ignore
|
+
| 6.0
* ''Statement body should be inside '{ }' braces.'' (Orion)
+
| ''Statements should be enclosed in braces.''
* ''Expected '{'.'' (Regular JSLint)
+
| &nbsp;
|  
+
 
|-
 
|-
  
 
!| dot-notation
 
!| dot-notation
| '''sub'''
+
| Warning
 +
| -
 
| ''{a} is better written in dot notation.''
 
| ''{a} is better written in dot notation.''
|  
+
| &nbsp;
 
|-
 
|-
  
!| eqeqeq
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 eqeqeq]</del>
| '''eqeqeq''' or '''eqeq'''
+
| Warning
 +
| 5.0
 
|
 
|
 
* ''Expected '===' and saw '=='.''
 
* ''Expected '===' and saw '=='.''
 
* ''Expected '!==' and saw '!='.''
 
* ''Expected '!==' and saw '!='.''
|
+
| &nbsp;
* Newer versions of JSLint call this option '''eqeqeq'''.
+
* Orion's version calls it '''eqeq''', and inverts the flag's value.
+
 
|-
 
|-
  
 
!| guard-for-in
 
!| guard-for-in
| '''forin'''
+
| Ignore
 +
| -
 
| ''The body of a <code>for in</code> should be wrapped in an <code>if</code> statement to filter unwanted properties from the prototype.''
 
| ''The body of a <code>for in</code> should be wrapped in an <code>if</code> statement to filter unwanted properties from the prototype.''
 +
| &nbsp;
 
|-
 
|-
  
 
!| max-depth
 
!| max-depth
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Enforces max depth of nested blocks within a function.
 
| Enforces max depth of nested blocks within a function.
 
|-
 
|-
  
 
!| max-len
 
!| max-len
| '''maxlen'''
+
| Ignore
| ''Line too long.''
+
| -
 +
| ''Line is too long.''
 
| Enforces a maximum line length.
 
| Enforces a maximum line length.
 
|-
 
|-
  
 
!| max-params
 
!| max-params
| Unsupported
+
| Ignore
|
+
| -
 +
| &nbsp;
 +
| &nbsp;
 
|-
 
|-
  
 
!| max-statements
 
!| max-statements
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 +
| &nbsp;
 +
|-
 +
 
 +
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=424128 missing-doc]</del>
 +
| Ignore
 +
| 5.0
 +
| "Missing documentation for function '{name}.'"
 +
| Flags missing documentation nodes on function declarations and function expressions when they appear as object properties
 +
|-
 +
 
 +
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=424204 missing-doc-items]
 +
| Ignore
 +
| -
 +
|&nbsp;
 +
| Flags missing documentation for parameters, returns, throws, etc on function declarations and function expressions when they appear as object properties
 +
|-
 +
 
 +
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=428429 missing-nls]
 +
| Ignore
 +
| -
 +
| &nbsp;
 +
| Flags String literals that are not properly NLS'd
 
|-
 
|-
  
 
!| new-cap
 
!| new-cap
| '''newcap'''
+
| Warning
 +
| -
 
| ''A constructor name should start with an uppercase letter.''
 
| ''A constructor name should start with an uppercase letter.''
 +
| &nbsp;
 
|-
 
|-
  
!| new-parens
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=429801 new-parens]</del>
| Always on
+
| Error
| ''Missing '()' invoking a constructor.''
+
| 6.0
 +
| ''Missing parentheses invoking constructor.''
 
| Flags <code>new Whatever</code>  
 
| Flags <code>new Whatever</code>  
 
|-
 
|-
  
 
!| no-alert
 
!| no-alert
| '''devel'''
+
| Ignore
 +
| -
 
| '''{alert, confirm, prompt}' is not defined.''
 
| '''{alert, confirm, prompt}' is not defined.''
|  
+
| &nbsp;
 
|-
 
|-
  
 
!| no-bitwise
 
!| no-bitwise
| '''bitwise'''
+
| Warning
 +
| -
 
| ''Unexpected use of '{operator}'.''
 
| ''Unexpected use of '{operator}'.''
 
| JSLint disallows bitwise ops by default.
 
| JSLint disallows bitwise ops by default.
Line 118: Line 159:
  
 
!| no-caller
 
!| no-caller
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags references to <code>arguments.callee</code> and <code>arguments.caller</code>.
 
| Flags references to <code>arguments.callee</code> and <code>arguments.caller</code>.
 
|-
 
|-
  
 
!| no-catch-shadow
 
!| no-catch-shadow
| Always on
+
| Warning
 +
| -
 
| '''{a}' is already defined.''
 
| '''{a}' is already defined.''
 
|
 
|
* Flags a <code>catch</code> clause's variable that shadows a variable declared in an outer scope. (In IE8 this [weblog.bocoup.com/the-catch-with-try-catch/ causes the outer variable to be overwritten]).
+
* Flags a <code>catch</code> clause's variable that shadows a variable declared in an outer scope. (In IE8 this [http://weblog.bocoup.com/the-catch-with-try-catch/ causes the outer variable to be overwritten]).
 
|-
 
|-
  
!| no-comma-dangle
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=426723 no-comma-dangle]
| Always on
+
| Warning
 +
| -
 
| ''Unexpected comma.''
 
| ''Unexpected comma.''
| Flags trailing commas in object literals.
+
| Flags trailing commas in object literals and array declarations.
 
|-
 
|-
  
 
!| no-cond-assign
 
!| no-cond-assign
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags assignment in an <code>if/while/do..while/for</code> condition.
 
| Flags assignment in an <code>if/while/do..while/for</code> condition.
 
|-
 
|-
  
 
!| no-console
 
!| no-console
| '''devel'''
+
| Ignore
|  
+
| -
|  
+
| &nbsp;
 +
| &nbsp;
 
|-
 
|-
  
 
!| no-control-regex
 
!| no-control-regex
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags control characters (U+0000–U+001F and U+007F) within the source argument to the RegExp constructor.
 
| Flags control characters (U+0000–U+001F and U+007F) within the source argument to the RegExp constructor.
 
|-
 
|-
  
!| no-debugger
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=429690 no-debugger]</del>
| '''debug'''
+
| Warning
| ''All 'debugger' statements should be removed.''
+
| 6.0
|  
+
| ''debugger' statement use is discouraged.''
 +
| &nbsp;
 
|-
 
|-
  
 
!| no-delete-var
 
!| no-delete-var
| Always on
+
| Warning
| ''Expected '.' and instead saw ';'.''
+
| -
 +
| ''Deleting a local variable is discouraged.''
 
| Flags an attempt to <code>delete</code> a local variable.
 
| Flags an attempt to <code>delete</code> a local variable.
 
|-
 
|-
  
 
!| no-div-regex
 
!| no-div-regex
| Always on
+
| Warning
 +
| -
 
| ''A regular expression literal can be confused with '/='.''
 
| ''A regular expression literal can be confused with '/='.''
 
| Flags a regex literal starting with <code>/=</code>
 
| Flags a regex literal starting with <code>/=</code>
 
|-
 
|-
  
!| no-dupe-keys
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=428430 no-dupe-keys]</del>
| Always on
+
| Error
| ''Duplicate key '{a}'.''
+
| 6.0
 +
| ''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.
 
|-
 
|-
  
 
!| no-else-return
 
!| no-else-return
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags an <code>else</code> appearing after an <code>if</code> that contains a <code>return</code>.
 
| Flags an <code>else</code> appearing after an <code>if</code> that contains a <code>return</code>.
 
|-
 
|-
  
 
!| no-empty-class
 
!| no-empty-class
| Always on
+
| Warning
 +
| -
 
| ''Empty class.''
 
| ''Empty class.''
 
| Flags an empty character class <code>[]</code> within a regular expression.
 
| Flags an empty character class <code>[]</code> within a regular expression.
Line 191: Line 244:
  
 
!| no-empty-label
 
!| no-empty-label
| Always on
+
| Warning
| ''Label '{a}' on statement.''
+
| -
 +
| ''Label '{a}' is not allowed on this statement.''
 
| Flags a labeled statement that is not a <code>switch</code>, <code>for</code>, or <code>while</code>.
 
| Flags a labeled statement that is not a <code>switch</code>, <code>for</code>, or <code>while</code>.
 
|-
 
|-
  
 
!| no-empty
 
!| no-empty
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags an empty block like <code>if (something) { }</code>.
 
| Flags an empty block like <code>if (something) { }</code>.
 
|-
 
|-
  
 
!| no-eq-null
 
!| no-eq-null
| Always on
+
| Error
 +
| -
 
| ''Use '===' to compare with 'null'.''
 
| ''Use '===' to compare with 'null'.''
| JSLint produces a similar warning when comparing against <code>undefined</code>.
+
| &nbsp;
 
|-
 
|-
  
!| no-eval
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=429702 no-eval]</del>
| '''evil'''
+
| Ignore
| ''eval is evil.''
+
| 6.0
 +
| '''eval' function calls are discouraged.''
 +
| &nbsp;
 
|-
 
|-
  
 
!| no-ex-assign
 
!| no-ex-assign
| Always on
+
| Warning
 +
| -
 
| ''Do not assign to the exception parameter.''
 
| ''Do not assign to the exception parameter.''
 +
| &nbsp;
 
|-
 
|-
  
!| no-extra-semi
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=428040 no-extra-semi]</del>
| Always on
+
| Warning
 +
| 5.0
 
| ''Unnecessary semicolon.''
 
| ''Unnecessary semicolon.''
 +
| &nbsp;
 
|-
 
|-
  
!| no-fallthrough
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429815 no-fallthrough]
| Unsupported
+
| Error
|  
+
| -
 +
| ''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 <code>switch</code> statement, unless it is explicitly commented.
 
| Flags a fallthrough case within a <code>switch</code> statement, unless it is explicitly commented.
 
|-
 
|-
  
 
!| no-floating-decimal
 
!| no-floating-decimal
| Always on
+
| Warning
 +
| -
 
| ''A {leading, trailing} decimal point can be confused with a dot: '{n}'.''
 
| ''A {leading, trailing} decimal point can be confused with a dot: '{n}'.''
 
| Flags numeric literals that have a leading or trailing decimal point.
 
| Flags numeric literals that have a leading or trailing decimal point.
Line 236: Line 300:
  
 
!| no-func-assign
 
!| no-func-assign
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags assignment to a variable that's already bound to a <code>FunctionExpression</code>.
 
| Flags assignment to a variable that's already bound to a <code>FunctionExpression</code>.
 
|-
 
|-
  
 
!| no-global-strict
 
!| no-global-strict
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags <code>"use strict"</code> applied to the entire Program.
 
| Flags <code>"use strict"</code> applied to the entire Program.
 
|-
 
|-
  
!| no-implied-eval
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=429707 no-implied-eval]</del>
| Always on
+
| Ignore
| ''Implied eval is evil. Pass a function instead of a string.''
+
| 6.0
| Flags calls to the string-argument form of <code>setTimeout</code> and <code>setInterval</code>, which implicitly perform <code>eval</code>.
+
| ''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.
 
|-
 
|-
  
 
!| no-iterator
 
!| no-iterator
| Always on
+
| Error
 +
| -
 
| ''Reserved name '__iterator__'.''
 
| ''Reserved name '__iterator__'.''
 
| Flags use of __iterator__ as an identifier name or property key.
 
| Flags use of __iterator__ as an identifier name or property key.
Line 260: Line 328:
  
 
!| no-label-var
 
!| no-label-var
| Always on
+
| Error
 +
| -
 
| '''{label}' is already defined.''
 
| '''{label}' is already defined.''
 
| Flags labels that collide with an identifier.
 
| Flags labels that collide with an identifier.
Line 266: Line 335:
  
 
!| no-loop-func
 
!| no-loop-func
| Always on
+
| Error
 +
| -
 
| ''Don't make functions within a loop.''
 
| ''Don't make functions within a loop.''
|
+
| &nbsp;
 
|-
 
|-
  
 
!| no-mixed-requires
 
!| no-mixed-requires
|  
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags Node.js <code>require()</code>s that mix different types of requires (core, module, file, computed).
 
| Flags Node.js <code>require()</code>s that mix different types of requires (core, module, file, computed).
 +
|-
 +
 +
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=425200 no-mixed-returns]
 +
| Error
 +
| -
 +
| &nbsp;
 +
| Flags functions that return more than one kind of item, for example returning String and Object
 
|-
 
|-
  
 
!| no-multi-str
 
!| no-multi-str
|  
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags use of ES5 multiline string literals.
 
| Flags use of ES5 multiline string literals.
 
|-
 
|-
  
 
!| no-native-reassign
 
!| no-native-reassign
| Always on
+
| Warning
 +
| -
 
|
 
|
 
* ''Read only.''
 
* ''Read only.''
Line 292: Line 372:
  
 
!| no-negated-in-lhs
 
!| no-negated-in-lhs
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
|
 
|
 
* Flags a unary <code>!</code> operator applied to the LHS of an in statement, which negates the LHS, not the <code>in</code>.  
 
* Flags a unary <code>!</code> operator applied to the LHS of an in statement, which negates the LHS, not the <code>in</code>.  
Line 299: Line 380:
 
|-
 
|-
  
!| no-new-array
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429817 no-new-array]
| Always on
+
| Warning
 +
| -
 
| ''Use the array literal notation [].''
 
| ''Use the array literal notation [].''
 
| Flags <code>new Array()</code>.
 
| Flags <code>new Array()</code>.
 
|-
 
|-
  
!| no-new-func
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429817 no-new-func]
| Always on
+
| Warning
 +
| -
 
| ''The Function constructor is eval.''
 
| ''The Function constructor is eval.''
|  
+
| Flags <code>new Function()</code>.
 
|-
 
|-
  
!| no-new-object
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429817 no-new-object]
| Always on
+
| Warning
 +
| -
 
| ''Use the object literal notation {}.''
 
| ''Use the object literal notation {}.''
 
| Flags <code>new Object()</code>.
 
| Flags <code>new Object()</code>.
 
|-
 
|-
  
!| no-new-wrappers
+
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=429817 no-new-wrappers]
|  
+
| Warning
 +
| -
 
| ''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.
Line 324: Line 409:
  
 
!| no-new
 
!| no-new
| Always on
+
| Error
 +
| -
 
| ''Do not use 'new' for side effects.''
 
| ''Do not use 'new' for side effects.''
 
| Flags uses of <code>new</code> operator in an expression that is not assigned to anything.
 
| Flags uses of <code>new</code> operator in an expression that is not assigned to anything.
Line 330: Line 416:
  
 
!| no-obj-calls
 
!| no-obj-calls
| Partial support
+
| Warning
 +
| -
 
| ''Math is not a function..''
 
| ''Math is not a function..''
 
|
 
|
 
* Flags attempts to call object properties of the global object (<code>Math</code>, <code>JSON</code>) as a function, like <code>Math()</code>.
 
* Flags attempts to call object properties of the global object (<code>Math</code>, <code>JSON</code>) as a function, like <code>Math()</code>.
* JSLint warns only on <code>Math()</code>.
 
 
|-
 
|-
  
 
!| no-octal-escape
 
!| no-octal-escape
| Always on
+
| Warning
 +
| -
 
| ''Bad escapement.''
 
| ''Bad escapement.''
 
| Flags octal escapes in strings, for example <code>var x = "Copyright \251";</code>
 
| Flags octal escapes in strings, for example <code>var x = "Copyright \251";</code>
Line 344: Line 431:
  
 
!| no-octal
 
!| no-octal
| Always on
+
| Warning
 +
| -
 
| ''Don't use extra leading zeros '{n}'.''
 
| ''Don't use extra leading zeros '{n}'.''
 
| Flags number literals that begin with leading 0s, which indicate a (probably accidental) octal literal.
 
| Flags number literals that begin with leading 0s, which indicate a (probably accidental) octal literal.
Line 350: Line 438:
  
 
!| no-plusplus
 
!| no-plusplus
| '''plusplus'''
+
| Warning
 +
| -
 
|  
 
|  
 
* ''Unexpected use of '++'''
 
* ''Unexpected use of '++'''
 
* ''Unexpected use of '--'''
 
* ''Unexpected use of '--'''
 +
| &nbsp;
 
|-
 
|-
  
 
!| no-proto
 
!| no-proto
| Always on
+
| Error
 +
| -
 
|
 
|
* ''Reserved name '__proto__'.'' (if used as an identifier)
+
* ''Reserved name '__proto__' should not be assigned."
* ''Stupid key '{a}'.'' (if used as a key)
+
* 'Reserved name '__proto__' should not be used as a key."
| Treated as a fatal parse error in JSLint.
+
| &nbsp;
 
|-
 
|-
  
!| no-redeclare
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 no-redeclare]</del>
| Always on
+
| Warning
 +
| 5.0
 
| '''{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>.
Line 371: Line 463:
  
 
!| no-return-assign
 
!| no-return-assign
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
|
 
|
 
* Prevents assignment in a <code>return</code> statement.
 
* Prevents assignment in a <code>return</code> statement.
Line 379: Line 472:
  
 
!| no-script-url
 
!| no-script-url
| Always on
+
| Warning
| ''Script URL.''
+
| -
 +
| &nbsp;
 
|  
 
|  
 
* Flags string literals beginning with <code>javascript:</code>. (Script URLs are a form of <code>eval</code>.)
 
* Flags string literals beginning with <code>javascript:</code>. (Script URLs are a form of <code>eval</code>.)
* Fatal parse error in JSLint.
 
 
|-
 
|-
  
 
!| no-self-compare
 
!| no-self-compare
| Unsupported
+
| Error
|
+
| -
 +
| &nbsp;
 
| Flags comparisons where the left- and right-hand sides are the same.
 
| Flags comparisons where the left- and right-hand sides are the same.
 
|-
 
|-
  
 
!!| no-shadow
 
!!| no-shadow
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags variables that have the same name as a variable declared in an outer scope.
 
| Flags variables that have the same name as a variable declared in an outer scope.
 
|-
 
|-
  
 
!| no-spaced-func
 
!| no-spaced-func
|  
+
| Ignore
|  
+
| -
 +
| ''Unnecessary space in function call.''
 +
| Report on excess space in a function call, for example <code>myFunc ();</code> or <code>new MyObj ();</code>
 
|-
 
|-
  
 
!| no-sync
 
!| no-sync
| '''stupid'''
+
| Ignore
 +
| -
 
| ''Unexpected sync method: '{a}'.''
 
| ''Unexpected sync method: '{a}'.''
 
|
 
|
Line 412: Line 510:
  
 
!| no-ternary
 
!| no-ternary
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags any use of the ternary operator <code>cond ? thenExpr : elseExpr</code>
 
| Flags any use of the ternary operator <code>cond ? thenExpr : elseExpr</code>
 
|-
 
|-
  
 
!| no-undef-init
 
!| no-undef-init
| Always on
+
| Warning
 +
| -
 
| ''It is not necessary to initialize '{variable}' to 'undefined'.''
 
| ''It is not necessary to initialize '{variable}' to 'undefined'.''
|  
+
| &nbsp;
 
|-
 
|-
  
!| no-undef
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=427310 no-unused-params]</del>
| '''undef'''
+
| Warning
 +
| -
 +
| "Parameter '{param}' is not used."
 +
| Flags parameters in function declarations / expressions if they are not being used
 +
|-
 +
 
 +
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 no-undef]</del>
 +
| Error
 +
| 5.0
 
| '''{variable}' is not defined.''
 
| '''{variable}' is not defined.''
 
|
 
|
Line 432: Line 540:
  
 
!| no-underscore-dangle
 
!| no-underscore-dangle
| '''nomen'''
+
| Ignore
 +
| -
 
| ''Dangling '_'''
 
| ''Dangling '_'''
 +
| &nbsp;
 
|-
 
|-
  
 
!| no-unreachable
 
!| no-unreachable
| Always on
+
| Error
 +
| -
 
| ''Unreachable '{statement}' after '{control flow statement}'.''
 
| ''Unreachable '{statement}' after '{control flow statement}'.''
 
| Flags statements that occur after a <code>return</code>, <code>throw</code>, etc.
 
| Flags statements that occur after a <code>return</code>, <code>throw</code>, etc.
Line 443: Line 554:
  
 
!| no-unused-expressions
 
!| no-unused-expressions
| Always on
+
| Warning
 +
| -
 
| ''Expected an assignment or function call and instead saw an expression.''
 
| ''Expected an assignment or function call and instead saw an expression.''
 
| Flags expressions that appear in a statement context and don't cause side effects.
 
| Flags expressions that appear in a statement context and don't cause side effects.
 
|-
 
|-
  
!| no-unused-vars
+
!| <deL>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 no-unused-vars]</del>
| Always on
+
| Warning
| ''Function declares unused variable '{a}'.'' (Orion)
+
| 5.0
| Newer JSlint versions have an '''unparam''' option which works similarly.
+
| ''Function declares unused variable '{a}'.''
 +
| &nbsp;
 
|-
 
|-
  
!| no-use-before-define
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=414779 no-use-before-define]</del>
| Always on
+
| Warning
 +
| 5.0
 
| '''{a}' was used before it was defined.''
 
| '''{a}' was used before it was defined.''
 +
| &nbsp;
 
|-
 
|-
  
 
!| no-with
 
!| no-with
| Always on
+
| Warning
 +
| -
 
| ''Expected an identifier and instead saw 'with'.''
 
| ''Expected an identifier and instead saw 'with'.''
 
| Treated as fatal parse error in JSLint.
 
| Treated as fatal parse error in JSLint.
Line 466: Line 582:
  
 
!| no-wrap-func
 
!| no-wrap-func
| Always on
+
| Ignore
 +
| -
 
| ''Do not wrap function literals in parens unless they are to be immediately invoked.''
 
| ''Do not wrap function literals in parens unless they are to be immediately invoked.''
 
| Flags a parenthesized function literal that is not immediately invoked, eg. <code>(function fun(){})</code>
 
| Flags a parenthesized function literal that is not immediately invoked, eg. <code>(function fun(){})</code>
 +
|-
 +
 +
!| object-prototype-external
 +
| Warning
 +
| -
 +
| &nbsp;
 +
| Flags calls to methods of <code>Object.prototype</code> that rely on the prototype chain. For example this code should be flagged:
 +
<source lang="javascript" line="line">
 +
foo.hasOwnProperty("bar")
 +
</source>
 +
 +
Example (1) is [https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty?redirectlocale=en-US&redirectslug=JavaScript%2FReference%2FGlobal_Objects%2FObject%2FhasOwnProperty#hasOwnProperty_as_a_property unsafe], as <code>foo</code> may have a property named <code>hasOwnProperty</code>, or have been constructed via <code>Object.create(null)</code>.
 +
 +
As for this:
 +
 +
<source lang="javascript" line="line" start="2">
 +
Object.hasOwnProperty.call(foo, "bar")
 +
</source>
 +
 +
Example (2) technically relies on the prototype chain as well: the hasOwnProperty method is defined on Object.prototype, not Object. Object inherits the methods of Object.prototype [http://stackoverflow.com/questions/14817826/difference-between-an-object-and-its-prototype/14817913#14817913 through its prototype chain]. However (2) is unlikely to fail, as sane JavaScript programs will not modify the global objects' prototypes. If we choose to flag (2), it should only be for style.
 
|-
 
|-
  
 
!| one-var
 
!| one-var
| '''onevar'''
+
| Warning
 +
| -
 
| ''Too many var statements.''
 
| ''Too many var statements.''
 
| Allows only 1 <code>var</code> statement per function.
 
| Allows only 1 <code>var</code> statement per function.
Line 478: Line 616:
  
 
!| quote-props
 
!| quote-props
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Requires object literal keys to be quoted with " or '.
 
| Requires object literal keys to be quoted with " or '.
 
|-
 
|-
  
 
!| quotes
 
!| quotes
| Unsupported
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags any use of single or double quote marks, depending on setting.
 
| Flags any use of single or double quote marks, depending on setting.
 
|-
 
|-
  
 
!| radix
 
!| radix
| Always on
+
| Warning
 +
| -
 
| ''Missing radix parameter.''
 
| ''Missing radix parameter.''
 
| Affects parseInt().
 
| Affects parseInt().
Line 496: Line 637:
  
 
!| regex-spaces
 
!| regex-spaces
| Always on
+
| Warning
 +
| -
 
| ''Spaces are hard to count. Use {n}.''
 
| ''Spaces are hard to count. Use {n}.''
 +
| &nbsp;
 
|-
 
|-
  
!| semi
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=427930 semi]</del>
| Always on
+
| Warning
 +
| 5.0
 
| ''Missing semicolon.''
 
| ''Missing semicolon.''
|
+
| &nbsp;
 
|-
 
|-
  
 
!| strict
 
!| strict
| '''strict'''
+
| Ignore
|  
+
| -
 +
| &nbsp;
 
| Flags any code that lacks the <code>"use strict"</code> pragma.
 
| Flags any code that lacks the <code>"use strict"</code> pragma.
 
|-
 
|-
  
 
!| unnecessary-strict
 
!| unnecessary-strict
| Unsupported
+
| Warning
|  
+
| -
 +
| &nbsp;
 
| Flags <code>"use strict"</code> on a function when the entire Program is already in strict mode.
 
| Flags <code>"use strict"</code> on a function when the entire Program is already in strict mode.
 
|-
 
|-
  
!| use-isnan
+
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=429711 use-isnan]</del>
| Always on
+
| Error
 +
| 6.0
 
| ''Use the isNaN function to compare with NaN.''
 
| ''Use the isNaN function to compare with NaN.''
|
+
| &nbsp;
 
|-
 
|-
  
 
!| wrap-iife
 
!| wrap-iife
| '''immed'''
+
| Ignore
 +
| -
 
|
 
|
 
* ''Wrap the entire immediate function invocation in parens.''
 
* ''Wrap the entire immediate function invocation in parens.''
Line 533: Line 681:
  
 
!| wrap-regex
 
!| wrap-regex
| Always on
+
| Warning
 +
| -
 
| ''Wrap the /regexp/ literal in parens to disambiguate the slash operator.''
 
| ''Wrap the /regexp/ literal in parens to disambiguate the slash operator.''
 +
| &nbsp;
 
|-
 
|-
  
  
 
|}
 
|}
 
== New rules ==
 
Ideas for new linting rules that we should write.
 
 
{| class="wikitable" border="1" cellpadding="5" cellspacing="0" style="width: 100%;"
 
! style="background:#efefef;" | Name
 
! style="background:#efefef;" | Severity
 
! style="background:#efefef;" | Description
 
|-
 
!| object-prototype-external
 
| Warning
 
| Flags calls to methods of <code>Object.prototype</code> that rely on the prototype chain. For example this code should be flagged:
 
<source lang="javascript" line="line">
 
foo.hasOwnProperty("bar")
 
</source>
 
 
Example (1) is [https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty?redirectlocale=en-US&redirectslug=JavaScript%2FReference%2FGlobal_Objects%2FObject%2FhasOwnProperty#hasOwnProperty_as_a_property unsafe], as <code>foo</code> may have a property named <code>hasOwnProperty</code>, or have been constructed via <code>Object.create(null)</code>.
 
 
As for this:
 
 
<source lang="javascript" line="line" start="2">
 
Object.hasOwnProperty.call(foo, "bar")
 
</source>
 
 
Example (2) technically relies on the prototype chain as well: the hasOwnProperty method is defined on Object.prototype, not Object. Object inherits the methods of Object.prototype [http://stackoverflow.com/questions/14817826/difference-between-an-object-and-its-prototype/14817913#14817913 through its prototype chain]. However (2) is unlikely to fail, as sane JavaScript programs will not modify the global objects' prototypes. If we choose to flag (2), it should only be for style.
 
|-
 
!| <del>[https://bugs.eclipse.org/bugs/show_bug.cgi?id=424128 missing-doc]</del>
 
| Ignore
 
| Flags missing documentation nodes on function declarations and function expressions when they appear as object properties
 
|-
 
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=424204 missing-doc-items]
 
| Ignore
 
| Flags missing documentation for parameters, returns, throws, etc on function declarations and function expressions when they appear as object properties
 
|-
 
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=427310 unused-parameters]
 
| Error
 
| Flags parameters in function declarations / expressions if they are not being used
 
|-
 
!| [https://bugs.eclipse.org/bugs/show_bug.cgi?id=425200 no-mixed-returns]
 
| Error
 
| Flags functions that return more than one kind of item, for example returning String and Object
 
|}
 
 
== Rule priority ==
 
Here are the rules we want to support, grouped by priority. Implemented rules are <del>struck out</del>.
 
 
==== Critical ====
 
* block-scoped-var
 
* <del>eqeqeq</del>
 
* <del>no-undef</del>
 
* <del>no-redeclare</del>
 
* <del>no-unused-vars</del>
 
* <del>no-use-before-define</del>
 
 
==== Important ====
 
* guard-for-in
 
* no-dupe-keys
 
* no-octal
 
* no-with
 
* radix
 
* <del>semi</del>
 
* wrap-iife
 
 
==== Nice to have ====
 
* dot-notation
 
* new-cap
 
* new-parens
 
* no-caller
 
* no-comma-dangle
 
* no-implied-eval
 
* no-new-array
 
* no-new-object
 
* no-undef-init
 
* no-unused-expressions
 
* no-wrap-func
 
* use-isnan
 
  
 
== Tests ==
 
== Tests ==
Line 674: Line 748:
  
 
== User interface ==
 
== User interface ==
* <del>Should we have a UI for configuring what rules are active?</del> Implemented.
+
* <del>Should we have a UI for configuring what rules are active?</del> [https://bugs.eclipse.org/bugs/show_bug.cgi?id=424268 bug 424268].
 
* Should we try to support <code>.eslintrc</code>? This would be an ideal project-scope setting.
 
* Should we try to support <code>.eslintrc</code>? This would be an ideal project-scope setting.
 
* Should we try to honor equivalent JSLint/JSHint flags when possible? For example <code>/*jslint eqeqeq:false */</code> could disable the eqeqeq rule on a per-file basis.
 
* Should we try to honor equivalent JSLint/JSHint flags when possible? For example <code>/*jslint eqeqeq:false */</code> could disable the eqeqeq rule on a per-file basis.

Revision as of 16:56, 3 April 2014

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

Rules

The following table describes all of the rules currently available in Orion and ones that we plan to add in the future.

Rules that are currently available are struck out.

Rule Default Severity Available Since Problem Message Details
block-scoped-var Error - '{variable}' is already defined.
  • Occurs when a function-scoped variable is treated as if it was block scoped.
  • ESLint calls this error '{variable} used outside of binding context.'
brace-style Ignore -    
camelcase Ignore -    
complexity Ignore -    
consistent-this Ignore -    
curly Ignore 6.0 Statements should be enclosed in braces.  
dot-notation Warning - {a} is better written in dot notation.  
eqeqeq Warning 5.0
  • Expected '===' and saw '=='.
  • Expected '!==' and saw '!='.
 
guard-for-in Ignore - The body of a for in should be wrapped in an if statement to filter unwanted properties from the prototype.  
max-depth Ignore -   Enforces max depth of nested blocks within a function.
max-len Ignore - Line is too long. Enforces a maximum line length.
max-params Ignore -    
max-statements Ignore -    
missing-doc Ignore 5.0 "Missing documentation for function '{name}.'" Flags missing documentation nodes on function declarations and function expressions when they appear as object properties
missing-doc-items Ignore -   Flags missing documentation for parameters, returns, throws, etc on function declarations and function expressions when they appear as object properties
missing-nls Ignore -   Flags String literals that are not properly NLS'd
new-cap Warning - A constructor name should start with an uppercase letter.  
new-parens Error 6.0 Missing parentheses invoking constructor. Flags new Whatever
no-alert Ignore - '{alert, confirm, prompt}' is not defined.  
no-bitwise Warning - Unexpected use of '{operator}'. JSLint disallows bitwise ops by default.
no-caller Ignore -   Flags references to arguments.callee and arguments.caller.
no-catch-shadow Warning - '{a}' is already defined.
no-comma-dangle Warning - Unexpected comma. Flags trailing commas in object literals and array declarations.
no-cond-assign Ignore -   Flags assignment in an if/while/do..while/for condition.
no-console Ignore -    
no-control-regex Ignore -   Flags control characters (U+0000–U+001F and U+007F) within the source argument to the RegExp constructor.
no-debugger Warning 6.0 debugger' statement use is discouraged.  
no-delete-var Warning - Deleting a local variable is discouraged. Flags an attempt to delete a local variable.
no-div-regex Warning - A regular expression literal can be confused with '/='. Flags a regex literal starting with /=
no-dupe-keys Error 6.0 Duplicate object key '{key}'. Flags object literals that contain the same key more than once.
no-else-return Warning -   Flags an else appearing after an if that contains a return.
no-empty-class Warning - Empty class. Flags an empty character class [] within a regular expression.
no-empty-label Warning - Label '{a}' is not allowed on this statement. Flags a labeled statement that is not a switch, for, or while.
no-empty Warning -   Flags an empty block like if (something) { }.
no-eq-null Error - Use '===' to compare with 'null'.  
no-eval Ignore 6.0 'eval' function calls are discouraged.  
no-ex-assign Warning - Do not assign to the exception parameter.  
no-extra-semi Warning 5.0 Unnecessary semicolon.  
no-fallthrough Error - 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-floating-decimal Warning - A {leading, trailing} decimal point can be confused with a dot: '{n}'. Flags numeric literals that have a leading or trailing decimal point.
no-func-assign Warning -   Flags assignment to a variable that's already bound to a FunctionExpression.
no-global-strict Warning -   Flags "use strict" applied to the entire Program.
no-implied-eval Ignore 6.0 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 - Reserved name '__iterator__'. Flags use of __iterator__ as an identifier name or property key.
no-label-var Error - '{label}' is already defined. Flags labels that collide with an identifier.
no-loop-func Error - Don't make functions within a loop.  
no-mixed-requires Ignore -   Flags Node.js require()s that mix different types of requires (core, module, file, computed).
no-mixed-returns Error -   Flags functions that return more than one kind of item, for example returning String and Object
no-multi-str Warning -   Flags use of ES5 multiline string literals.
no-native-reassign Warning -
  • Read only.
  • Bad assignment. (if assigning to undefined)
Flags an attempt to reassign a native object like Math, Array, undefined, etc.
no-negated-in-lhs Warning -  
  • Flags a unary ! operator applied to the LHS of an in statement, which negates the LHS, not the in.
  • Eg. (!"key" in {key: 1}) (which always evaluates to false), will be flagged.
no-new-array Warning - Use the array literal notation []. Flags new Array().
no-new-func Warning - The Function constructor is eval. Flags new Function().
no-new-object Warning - Use the object literal notation {}. Flags new Object().
no-new-wrappers Warning - Do not use {String, Number, Boolean, Math, JSON} as a constructor. Flags new applied to any of those.
no-new Error - Do not use 'new' for side effects. Flags uses of new operator in an expression that is not assigned to anything.
no-obj-calls Warning - Math is not a function..
  • Flags attempts to call object properties of the global object (Math, JSON) as a function, like Math().
no-octal-escape Warning - Bad escapement. Flags octal escapes in strings, for example var x = "Copyright \251";
no-octal Warning - Don't use extra leading zeros '{n}'. Flags number literals that begin with leading 0s, which indicate a (probably accidental) octal literal.
no-plusplus Warning -
  • Unexpected use of '++'
  • Unexpected use of '--'
 
no-proto Error -
  • Reserved name '__proto__' should not be assigned."
  • 'Reserved name '__proto__' should not be used as a key."
 
no-redeclare Warning 5.0 '{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-return-assign Warning -  
  • Prevents assignment in a return statement.
  • Unsupported by JSLint, although JSLint does require parens around a return-assignment, eg: return (x = 2);
no-script-url Warning -  
  • Flags string literals beginning with javascript:. (Script URLs are a form of eval.)
no-self-compare Error -   Flags comparisons where the left- and right-hand sides are the same.
no-shadow Warning -   Flags variables that have the same name as a variable declared in an outer scope.
no-spaced-func Ignore - Unnecessary space in function call. Report on excess space in a function call, for example myFunc (); or new MyObj ();
no-sync Ignore - Unexpected sync method: '{a}'.
  • Flags Node.js's synchronous I/O methods.
  • The stupid option is supported only in newer versions of JSLint (not Orion's).
no-ternary Ignore -   Flags any use of the ternary operator cond ? thenExpr : elseExpr
no-undef-init Warning - It is not necessary to initialize '{variable}' to 'undefined'.  
no-unused-params Warning - "Parameter '{param}' is not used." Flags parameters in function declarations / expressions if they are not being used
no-undef Error 5.0 '{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) can be set in the /*jslint */ block.
no-underscore-dangle Ignore - Dangling '_'  
no-unreachable Error - Unreachable '{statement}' after '{control flow statement}'. Flags statements that occur after a return, throw, etc.
no-unused-expressions Warning - Expected an assignment or function call and instead saw an expression. Flags expressions that appear in a statement context and don't cause side effects.
no-unused-vars Warning 5.0 Function declares unused variable '{a}'.  
no-use-before-define Warning 5.0 '{a}' was used before it was defined.  
no-with Warning - Expected an identifier and instead saw 'with'. Treated as fatal parse error in JSLint.
no-wrap-func Ignore - Do not wrap function literals in parens unless they are to be immediately invoked. Flags a parenthesized function literal that is not immediately invoked, eg. (function fun(){})
object-prototype-external Warning -   Flags calls to methods of Object.prototype that rely on the prototype chain. For example this code should be flagged:
  1. foo.hasOwnProperty("bar")

Example (1) is unsafe, as foo may have a property named hasOwnProperty, or have been constructed via Object.create(null).

As for this:

  1. Object.hasOwnProperty.call(foo, "bar")

Example (2) technically relies on the prototype chain as well: the hasOwnProperty method is defined on Object.prototype, not Object. Object inherits the methods of Object.prototype through its prototype chain. However (2) is unlikely to fail, as sane JavaScript programs will not modify the global objects' prototypes. If we choose to flag (2), it should only be for style.

one-var Warning - Too many var statements. Allows only 1 var statement per function.
quote-props Warning -   Requires object literal keys to be quoted with " or '.
quotes Ignore -   Flags any use of single or double quote marks, depending on setting.
radix Warning - Missing radix parameter. Affects parseInt().
regex-spaces Warning - Spaces are hard to count. Use {n}.  
semi Warning 5.0 Missing semicolon.  
strict Ignore -   Flags any code that lacks the "use strict" pragma.
unnecessary-strict Warning -   Flags "use strict" on a function when the entire Program is already in strict mode.
use-isnan Error 6.0 Use the isNaN function to compare with NaN.  
wrap-iife Ignore -
  • Wrap the entire immediate function invocation in parens.
  • Move the invocation into the parens that contain the function.
Flags missing parens on immediately-invoked functions, eg. function(){ console.log('hi'); }();
wrap-regex Warning - Wrap the /regexp/ literal in parens to disambiguate the slash operator.  

Tests

  • Every rule needs extensive unit tests
  • Unit tests should use Mocha

Currently the tests are run from Node.js. They do not run in the browser (yet).

Test requirements

First install Node.js. Then open a console and install Mocha globally:

$ npm install mocha -g

Then from your Orion client repository, run these commands to install eslint's dependencies:

$ cd bundles/org.eclipse.orion.client.javascript/web/eslint/
$ npm install

Running the tests

From the bundles/org.eclipse.orion.client.javascript/web/eslint/ directory, simply run npm test:

$ npm test

> eslint@0.2.0-dev test c:\Users\mamacdon\code\orion\client\bundles\org.eclipse.orion.client.javascript\web\eslint
> bash scripts/test.sh


  ......................................................................
  ...............

  85 passing (106ms)

To run only a subset of the tests, launch mocha from the command line, passing the test file:

$ mocha tests/lib/rules/semi.js

  ............

  12 passing (17ms)

You can also pass an entire directory:

$ mocha tests/lib/rules

  ......................................................................
  ..........

  80 passing (104ms)

To run only some tests from a file, use the --grep option:

$ mocha tests/lib/rules/semi.js --grep VariableDeclaration

  .

  1 passing (5ms)

See Mocha usage options for more.

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.
  • 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.
    • This would give compatibility with Orion codebase which uses these flags.
    • OTOH, eslint now has its own syntax for this: /*eslint ..*/, which we should perhaps use instead.

i18n

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