lodash/lodash._baseassign/index.js

/**
 * lodash 3.0.1 (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 baseCopy = require('lodash._basecopy'),
    keys = require('lodash.keys');

/**
 * The base implementation of `_.assign` without support for argument juggling,
 * multiple sources, and `this` binding `customizer` functions.
 *
 * @private
 * @param {Object} object The destination object.
 * @param {Object} source The source object.
 * @param {Function} [customizer] The function to customize assigning values.
 * @returns {Object} Returns the destination object.
 */
function baseAssign(object, source, customizer) {
  var props = keys(source);
  if (!customizer) {
    return baseCopy(source, object, props);
  }
  var index = -1,
      length = props.length;

  while (++index < length) {
    var key = props[index],
        value = object[key],
        result = customizer(value, source[key], key, object, source);

    if ((result === result ? result !== value : value === value) ||
        (typeof value == 'undefined' && !(key in object))) {
      object[key] = result;
    }
  }
  return object;
}

module.exports = baseAssign;