eslint/docs/rules/prefer-rest-params.md

   1 # Suggest using the rest parameters instead of `arguments` (prefer-rest-params)
   2
   3 There are rest parameters in ES2015.
   4 We can use that feature for variadic functions instead of the `arguments` variable.
   5
   6 `arguments` does not have methods of `Array.prototype`, so it's a bit of an inconvenience.
   7
   8 ## Rule Details
   9
  10 This rule is aimed to flag usage of `arguments` variables.
  11
  12 ## Examples
  13
  14 Examples of **incorrect** code for this rule:
  15
  16 ```js
  17 function foo() {
  18     console.log(arguments);
  19 }
  20
  21 function foo(action) {
  22     var args = Array.prototype.slice.call(arguments, 1);
  23     action.apply(null, args);
  24 }
  25
  26 function foo(action) {
  27     var args = [].slice.call(arguments, 1);
  28     action.apply(null, args);
  29 }
  30 ```
  31
  32 Examples of **correct** code for this rule:
  33
  34 ```js
  35 function foo(...args) {
  36     console.log(args);
  37 }
  38
  39 function foo(action, ...args) {
  40     action.apply(null, args); // or `action(...args)`, related to the `prefer-spread` rule.
  41 }
  42
  43 // Note: the implicit arguments can be overwritten.
  44 function foo(arguments) {
  45     console.log(arguments); // This is the first argument.
  46 }
  47 function foo() {
  48     var arguments = 0;
  49     console.log(arguments); // This is a local variable.
  50 }
  51 ```
  52
  53 ## When Not To Use It
  54
  55 This rule should not be used in ES3/5 environments.
  56
  57 In ES2015 (ES6) or later, if you don't want to be notified about `arguments` variables, then it's safe to disable this rule.
  58
  59 ## Related Rules
  60
  61 * [prefer-spread](prefer-spread.md)