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  # detect-indent [![Build Status](https://travis-ci.org/sindresorhus/detect-indent.svg?branch=master)](https://travis-ci.org/sindresorhus/detect-indent)
  
  > Detect the indentation of code
  
  Pass in a string of any kind of text and get the indentation.
  
  
  ## Use cases
  
  - Persisting the indentation when modifying a file.
  - Have new content match the existing indentation.
  - Setting the right indentation in your editor.
  
  
  ## Install
  
  ```
  $ npm install --save detect-indent
  ```
  
  
  ## Usage
  
  Here we modify a JSON file while persisting the indentation:
  
  ```js
  var fs = require('fs');
  var detectIndent = require('detect-indent');
  
  /*
  {
      "ilove": "pizza"
  }
  */
  var file = fs.readFileSync('foo.json', 'utf8');
  
  // tries to detect the indentation and falls back to a default if it can't
  var indent = detectIndent(file).indent || '    ';
  
  var json = JSON.parse(file);
  
  json.ilove = 'unicorns';
  
  fs.writeFileSync('foo.json', JSON.stringify(json, null, indent));
  /*
  {
      "ilove": "unicorns"
  }
  */
  ```
  
  
  ## API
  
  Accepts a string and returns an object with stats about the indentation:  
  
  * `amount` {number} - Amount of indentation, e.g. `2`  
  * `type` {string|null} - Type of indentation. Possible values are `tab`, `space` or `null` if no indentation is detected  
  * `indent`   {string} - Actual indentation
  
  
  ## Algorithm
  
  The current algorithm looks for the most common difference between two consecutive non-empty lines.
  
  In the following example, even if the 4-space indentation is used 3 times whereas the 2-space one is used 2 times, it is detected as less used because there were only 2 differences with this value instead of 4 for the 2-space indentation:
  
  ```css
  html {
    box-sizing: border-box;
  }
  
  body {
    background: gray;
  }
  
  p {
      line-height: 1.3em;
      margin-top: 1em;
      text-indent: 2em;
  }
  ```
  
  [Source.](https://medium.com/@heatherarthur/detecting-code-indentation-eff3ed0fb56b#3918)
  
  Furthermore, if there are more than one most used difference, the indentation with the most lines is selected.
  
  In the following example, the indentation is detected as 4-spaces:
  
  ```css
  body {
    background: gray;
  }
  
  p {
      line-height: 1.3em;
      margin-top: 1em;
      text-indent: 2em;
  }
  ```
  
  
  ## Related
  
  - [detect-indent-cli](https://github.com/sindresorhus/detect-indent-cli) - CLI for this module
  
  
  ## License
  
  MIT © [Sindre Sorhus](http://sindresorhus.com)