Function _keys

lib/core.js:25–36

(obj)

 */

var _keys = function (obj) {
    if (Object.keys) {
        return Object.keys(obj);
    }
    var keys = [];
    for (var k in obj) {
        if (obj.hasOwnProperty(k)) {
            keys.push(k);
        }
    }
    return keys;
};


var _copy = function (obj) {