lodash/lodash._basecallback/index.js

/**
 * lodash 3.1.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modern modularize exports="npm" -o ./`
 * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.7.0 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var baseMatches = require('lodash._basematches'),
    baseProperty = require('lodash._baseproperty'),
    bindCallback = require('lodash._bindcallback');

/**
 * The base implementation of `_.callback` which supports specifying the
 * number of arguments to provide to `func`.
 *
 * @private
 * @param {*} [func=_.identity] The value to convert to a callback.
 * @param {*} [thisArg] The `this` binding of `func`.
 * @param {number} [argCount] The number of arguments to provide to `func`.
 * @returns {Function} Returns the callback.
 */
function baseCallback(func, thisArg, argCount) {
  var type = typeof func;
  if (type == 'function') {
    return (typeof thisArg != 'undefined')
      ? bindCallback(func, thisArg, argCount)
      : func;
  }
  if (func == null) {
    return identity;
  }
  // Handle "_.property" and "_.matches" style callback shorthands.
  return type == 'object'
    ? baseMatches(func)
    : baseProperty(func + '');
}

/**
 * This method returns the first argument provided to it.
 *
 * @static
 * @memberOf _
 * @category Utility
 * @param {*} value Any value.
 * @returns {*} Returns `value`.
 * @example
 *
 * var object = { 'user': 'fred' };
 * _.identity(object) === object;
 * // => true
 */
function identity(value) {
  return value;
}

module.exports = baseCallback;