ember-source/dist/packages/@ember/utils/lib/type-of.js

A JavaScript framework for creating ambitious web applications

import CoreObject from '../../object/core.js';

// ........................................
// TYPING & ARRAY MESSAGING
//
const TYPE_MAP = {
  '[object Boolean]': 'boolean',
  '[object Number]': 'number',
  '[object String]': 'string',
  '[object Function]': 'function',
  '[object AsyncFunction]': 'function',
  '[object Array]': 'array',
  '[object Date]': 'date',
  '[object RegExp]': 'regexp',
  '[object Object]': 'object',
  '[object FileList]': 'filelist'
};
const {
  toString
} = Object.prototype;

/**
 @module @ember/utils
*/
/**
  Returns a consistent type for the passed object.

  Use this instead of the built-in `typeof` to get the type of an item.
  It will return the same result across all browsers and includes a bit
  more detail. Here is what will be returned:

      | Return Value  | Meaning                                              |
      |---------------|------------------------------------------------------|
      | 'string'      | String primitive or String object.                   |
      | 'number'      | Number primitive or Number object.                   |
      | 'boolean'     | Boolean primitive or Boolean object.                 |
      | 'null'        | Null value                                           |
      | 'undefined'   | Undefined value                                      |
      | 'function'    | A function                                           |
      | 'array'       | An instance of Array                                 |
      | 'regexp'      | An instance of RegExp                                |
      | 'date'        | An instance of Date                                  |
      | 'filelist'    | An instance of FileList                              |
      | 'class'       | An Ember class (created using EmberObject.extend())  |
      | 'instance'    | An Ember object instance                             |
      | 'error'       | An instance of the Error object                      |
      | 'object'      | A JavaScript object not inheriting from EmberObject  |

  Examples:

  ```javascript
  import { A } from '@ember/array';
  import { typeOf } from '@ember/utils';
  import EmberObject from '@ember/object';

  typeOf();                       // 'undefined'
  typeOf(null);                   // 'null'
  typeOf(undefined);              // 'undefined'
  typeOf('michael');              // 'string'
  typeOf(new String('michael'));  // 'string'
  typeOf(101);                    // 'number'
  typeOf(new Number(101));        // 'number'
  typeOf(true);                   // 'boolean'
  typeOf(new Boolean(true));      // 'boolean'
  typeOf(A);                      // 'function'
  typeOf(A());                    // 'array'
  typeOf([1, 2, 90]);             // 'array'
  typeOf(/abc/);                  // 'regexp'
  typeOf(new Date());             // 'date'
  typeOf(event.target.files);     // 'filelist'
  typeOf(EmberObject.extend());   // 'class'
  typeOf(EmberObject.create());   // 'instance'
  typeOf(new Error('teamocil'));  // 'error'

  // 'normal' JavaScript object
  typeOf({ a: 'b' });             // 'object'
  ```

  @method typeOf
  @for @ember/utils
  @param item the item to check
  @return {String} the type
  @public
  @static
*/
function typeOf(item) {
  if (item === null) {
    return 'null';
  }
  if (item === undefined) {
    return 'undefined';
  }
  let ret = TYPE_MAP[toString.call(item)] || 'object';
  if (ret === 'function') {
    if (CoreObject.detect(item)) {
      ret = 'class';
    }
  } else if (ret === 'object') {
    if (item instanceof Error) {
      ret = 'error';
    } else if (item instanceof CoreObject) {
      ret = 'instance';
    } else if (item instanceof Date) {
      ret = 'date';
    }
  }
  return ret;
}

export { typeOf as default };