map-keys.js 372 Bytes
'use strict';

var callable = require('./valid-callable')
  , forEach  = require('./for-each')

  , call = Function.prototype.call;

module.exports = function (obj, cb/*, thisArg*/) {
	var o = {}, thisArg = arguments[2];
	callable(cb);
	forEach(obj, function (value, key, obj, index) {
		o[call.call(cb, thisArg, key, value, this, index)] = value;
	}, obj);
	return o;
};