eslint/docs/rules/no-func-assign.md

   1 # disallow reassigning `function` declarations (no-func-assign)
   2
   3 JavaScript functions can be written as a FunctionDeclaration `function foo() { ... }` or as a FunctionExpression `var foo = function() { ... };`. While a JavaScript interpreter might tolerate it, overwriting/reassigning a function written as a FunctionDeclaration is often indicative of a mistake or issue.
   4
   5 ```js
   6 function foo() {}
   7 foo = bar;
   8 ```
   9
  10 ## Rule Details
  11
  12 This rule disallows reassigning `function` declarations.
  13
  14 Examples of **incorrect** code for this rule:
  15
  16 ```js
  17 /*eslint no-func-assign: "error"*/
  18
  19 function foo() {}
  20 foo = bar;
  21
  22 function foo() {
  23     foo = bar;
  24 }
  25
  26 var a = function hello() {
  27   hello = 123;
  28 };
  29 ```
  30
  31 Examples of **incorrect** code for this rule, unlike the corresponding rule in JSHint:
  32
  33 ```js
  34 /*eslint no-func-assign: "error"*/
  35
  36 foo = bar;
  37 function foo() {}
  38 ```
  39
  40 Examples of **correct** code for this rule:
  41
  42 ```js
  43 /*eslint no-func-assign: "error"*/
  44
  45 var foo = function () {}
  46 foo = bar;
  47
  48 function foo(foo) { // `foo` is shadowed.
  49     foo = bar;
  50 }
  51
  52 function foo() {
  53     var foo = bar;  // `foo` is shadowed.
  54 }
  55 ```