source/pick.js

import _curry2 from './internal/_curry2.js';


/**
 * Returns a partial copy of an object containing only the keys specified. If
 * the key does not exist, the property is ignored.
 *
 * @func
 * @memberOf R
 * @since v0.1.0
 * @category Object
 * @sig [k] -> {k: v} -> {k: v}
 * @param {Array} names an array of String property names to copy onto a new object
 * @param {Object} obj The object to copy from
 * @return {Object} A new object with only properties from `names` on it.
 * @see R.omit, R.props
 * @example
 *
 *      R.pick(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
 *      R.pick(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1}
 */
var pick = _curry2(function pick(names, obj) {
  var result = {};
  var idx = 0;
  while (idx < names.length) {
    if (names[idx] in obj) {
      result[names[idx]] = obj[names[idx]];
    }
    idx += 1;
  }
  return result;
});
export default pick;