eslint/docs/rules/line-comment-position.md

   1 # enforce position of line comments (line-comment-position)
   2
   3 Line comments can be positioned above or beside code. This rule helps teams maintain a consistent style.
   4
   5 ```js
   6 // above comment
   7 var foo = "bar";  // beside comment
   8 ```
   9
  10 ## Rule Details
  11
  12 This rule enforces consistent position of line comments. Block comments are not affected by this rule. By default, this rule ignores comments starting with the following words: `eslint`, `jshint`, `jslint`, `istanbul`, `global`, `exported`, `jscs`, `falls through`.
  13
  14 ## Options
  15
  16 This rule takes one argument, which can be a string or an object. The string settings are the same as those of the `position` property (explained below). The object option has the following properties:
  17
  18 ### position
  19
  20 The `position` option has two settings:
  21
  22 * `above` (default) enforces line comments only above code, in its own line.
  23 * `beside` enforces line comments only at the end of code lines.
  24
  25 #### position: above
  26
  27 Examples of **correct** code for the `{ "position": "above" }` option:
  28
  29 ```js
  30 /*eslint line-comment-position: ["error", { "position": "above" }]*/
  31 // valid comment
  32 1 + 1;
  33 ```
  34
  35 Examples of **incorrect** code for the `{ "position": "above" }` option:
  36
  37 ```js
  38 /*eslint line-comment-position: ["error", { "position": "above" }]*/
  39 1 + 1; // invalid comment
  40 ```
  41
  42 #### position: beside
  43
  44 Examples of **correct** code for the `{ "position": "beside" }` option:
  45
  46 ```js
  47 /*eslint line-comment-position: ["error", { "position": "beside" }]*/
  48 1 + 1; // valid comment
  49 ```
  50
  51 Examples of **incorrect** code for the `{ "position": "beside" }` option:
  52
  53 ```js
  54 /*eslint line-comment-position: ["error", { "position": "beside" }]*/
  55 // invalid comment
  56 1 + 1;
  57 ```
  58
  59 ### ignorePattern
  60
  61 By default this rule ignores comments starting with the following words: `eslint`, `jshint`, `jslint`, `istanbul`, `global`, `exported`, `jscs`, `falls through`. An alternative regular expression can be provided.
  62
  63 Examples of **correct** code for the `ignorePattern` option:
  64
  65 ```js
  66 /*eslint line-comment-position: ["error", { "ignorePattern": "pragma" }]*/
  67 1 + 1; // pragma valid comment
  68 ```
  69
  70 Examples of **incorrect** code for the `ignorePattern` option:
  71
  72 ```js
  73 /*eslint line-comment-position: ["error", { "ignorePattern": "pragma" }]*/
  74 1 + 1; // invalid comment
  75 ```
  76
  77 ### applyDefaultIgnorePatterns
  78
  79 Default ignore patterns are applied even when `ignorePattern` is provided. If you want to omit default patterns, set this option to `false`.
  80
  81 Examples of **correct** code for the `{ "applyDefaultIgnorePatterns": false }` option:
  82
  83 ```js
  84 /*eslint line-comment-position: ["error", { "ignorePattern": "pragma", "applyDefaultIgnorePatterns": false }]*/
  85 1 + 1; // pragma valid comment
  86 ```
  87
  88 Examples of **incorrect** code for the `{ "applyDefaultIgnorePatterns": false }` option:
  89
  90 ```js
  91 /*eslint line-comment-position: ["error", { "ignorePattern": "pragma", "applyDefaultIgnorePatterns": false }]*/
  92 1 + 1; // falls through
  93 ```
  94
  95 **Deprecated:** the object property `applyDefaultPatterns` is deprecated. Please use the property `applyDefaultIgnorePatterns` instead.
  96
  97 ## When Not To Use It
  98
  99 If you aren't concerned about having different line comment styles, then you can turn off this rule.
 100
 101 ## Compatibility
 102
 103 **JSCS**: [validateCommentPosition](https://jscs-dev.github.io/rule/validateCommentPosition)