ES5 Object.assign 低版本浏览器内核兼容问题

var _extends = Object.assign || function (target) {
    for (var i = 1; i < arguments.length; i++) {
        var source = arguments[i];
        for (var key in source) {
            if (Object.prototype.hasOwnProperty.call(source, key)) {
                target[key] = source[key];
            }
        }
    }
    return target;
};