eslint/docs/rules/id-denylist.md

   1 # disallow specified identifiers (id-denylist)
   2
   3 > "There are only two hard things in Computer Science: cache invalidation and naming things." — Phil Karlton
   4
   5 Generic names can lead to hard-to-decipher code. This rule allows you to specify a deny list of disallowed identifier names to avoid this practice.
   6
   7 ## Rule Details
   8
   9 This rule disallows specified identifiers in assignments and `function` definitions.
  10
  11 This rule will catch disallowed identifiers that are:
  12
  13 - variable declarations
  14 - function declarations
  15 - object properties assigned to during object creation
  16
  17 It will not catch disallowed identifiers that are:
  18
  19 - function calls (so you can still use functions you do not have control over)
  20 - object properties (so you can still use objects you do not have control over)
  21
  22 ## Options
  23
  24 The rule takes one or more strings as options: the names of restricted identifiers.
  25
  26 For example, to restrict the use of common generic identifiers:
  27
  28 ```json
  29 {
  30     "id-denylist": ["error", "data", "err", "e", "cb", "callback"]
  31 }
  32 ```
  33
  34 Examples of **incorrect** code for this rule with sample `"data", "callback"` restricted identifiers:
  35
  36 ```js
  37 /*eslint id-denylist: ["error", "data", "callback"] */
  38
  39 var data = {...};
  40
  41 function callback() {
  42     // ...
  43 }
  44
  45 element.callback = function() {
  46     // ...
  47 };
  48
  49 var itemSet = {
  50     data: [...]
  51 };
  52 ```
  53
  54 Examples of **correct** code for this rule with sample `"data", "callback"` restricted identifiers:
  55
  56 ```js
  57 /*eslint id-denylist: ["error", "data", "callback"] */
  58
  59 var encodingOptions = {...};
  60
  61 function processFileResult() {
  62     // ...
  63 }
  64
  65 element.successHandler = function() {
  66     // ...
  67 };
  68
  69 var itemSet = {
  70     entities: [...]
  71 };
  72
  73 callback(); // all function calls are ignored
  74
  75 foo.callback(); // all function calls are ignored
  76
  77 foo.data; // all property names that are not assignments are ignored
  78 ```
  79
  80 ## When Not To Use It
  81
  82 You can turn this rule off if you do not want to restrict the use of certain identifiers.