eslint/docs/rules/no-mixed-spaces-and-tabs.md

   1 # disallow mixed spaces and tabs for indentation (no-mixed-spaces-and-tabs)
   2
   3 Most code conventions require either tabs or spaces be used for indentation. As such, it's usually an error if a single line of code is indented with both tabs and spaces.
   4
   5 ## Rule Details
   6
   7 This rule disallows mixed spaces and tabs for indentation.
   8
   9 Examples of **incorrect** code for this rule:
  10
  11 ```js
  12 /*eslint no-mixed-spaces-and-tabs: "error"*/
  13
  14 function add(x, y) {
  15 // --->..return x + y;
  16
  17       return x + y;
  18 }
  19
  20 function main() {
  21 // --->var x = 5,
  22 // --->....y = 7;
  23
  24     var x = 5,
  25         y = 7;
  26 }
  27 ```
  28
  29 Examples of **correct** code for this rule:
  30
  31 ```js
  32 /*eslint no-mixed-spaces-and-tabs: "error"*/
  33
  34 function add(x, y) {
  35 // --->return x + y;
  36     return x + y;
  37 }
  38 ```
  39
  40 ## Options
  41
  42 This rule has a string option.
  43
  44 * `"smart-tabs"` allows mixed tabs and spaces when the spaces are used for alignment.
  45
  46 ### smart-tabs
  47
  48 Examples of **correct** code for this rule with the `"smart-tabs"` option:
  49
  50 ```js
  51 /*eslint no-mixed-spaces-and-tabs: ["error", "smart-tabs"]*/
  52
  53 function main() {
  54 // --->var x = 5,
  55 // --->....y = 7;
  56
  57     var x = 5,
  58         y = 7;
  59 }
  60 ```
  61
  62
  63 ## Further Reading
  64
  65 * [Smart Tabs](https://www.emacswiki.org/emacs/SmartTabs)