eslint/docs/rules/func-call-spacing.md

   1 # require or disallow spacing between function identifiers and their invocations (func-call-spacing)
   2
   3 When calling a function, developers may insert optional whitespace between the function's name and the parentheses that invoke it. The following pairs of function calls are equivalent:
   4
   5 ```js
   6 alert('Hello');
   7 alert ('Hello');
   8
   9 console.log(42);
  10 console.log (42);
  11
  12 new Date();
  13 new Date ();
  14 ```
  15
  16 ## Rule Details
  17
  18 This rule requires or disallows spaces between the function name and the opening parenthesis that calls it.
  19
  20 ## options
  21
  22 This rule has a string option:
  23
  24 - `"never"` (default) disallows space between the function name and the opening parenthesis.
  25 - `"always"` requires space between the function name and the opening parenthesis.
  26
  27 Further, in `"always"` mode, a second object option is available that contains a single boolean `allowNewlines` property.
  28
  29 ### never
  30
  31 Examples of **incorrect** code for this rule with the default `"never"` option:
  32
  33 ```js
  34 /*eslint func-call-spacing: ["error", "never"]*/
  35
  36 fn ();
  37
  38 fn
  39 ();
  40 ```
  41
  42 Examples of **correct** code for this rule with the default `"never"` option:
  43
  44 ```js
  45 /*eslint func-call-spacing: ["error", "never"]*/
  46
  47 fn();
  48 ```
  49
  50 ### always
  51
  52 Examples of **incorrect** code for this rule with the `"always"` option:
  53
  54 ```js
  55 /*eslint func-call-spacing: ["error", "always"]*/
  56
  57 fn();
  58
  59 fn
  60 ();
  61 ```
  62
  63 Examples of **correct** code for this rule with the `"always"` option:
  64
  65 ```js
  66 /*eslint func-call-spacing: ["error", "always"]*/
  67
  68 fn ();
  69 ```
  70
  71 #### allowNewlines
  72
  73 By default, `"always"` does not allow newlines. To permit newlines when in `"always"` mode, set the `allowNewlines` option to `true`. Newlines are never required.
  74
  75 Examples of **incorrect** code for this rule with `allowNewlines` option enabled:
  76
  77 ```js
  78 /*eslint func-call-spacing: ["error", "always", { "allowNewlines": true }]*/
  79
  80 fn();
  81 ```
  82
  83 Examples of **correct** code for this rule with the `allowNewlines` option enabled:
  84
  85 ```js
  86 /*eslint func-call-spacing: ["error", "always", { "allowNewlines": true }]*/
  87
  88 fn (); // Newlines are never required.
  89
  90 fn
  91 ();
  92 ```
  93
  94 ## When Not To Use It
  95
  96 This rule can safely be turned off if your project does not care about enforcing a consistent style for spacing within function calls.
  97
  98 ## Related Rules
  99
 100 - [no-spaced-func](no-spaced-func.md) (deprecated)
 101
 102 ## Compatibility
 103
 104 - **JSCS**: [disallowSpacesInCallExpression](https://jscs-dev.github.io/rule/disallowSpacesInCallExpression)
 105 - **JSCS**: [requireSpacesInCallExpression](https://jscs-dev.github.io/rule/requireSpacesInCallExpression)