Function extend

libs/echarts/echarts-en.simple.js:412–419

* @param {*} target * @param {*} source * @memberOf module:zrender/core/util

(target, source)

 * @memberOf module:zrender/core/util
 */
function extend(target, source) {
    for (var key in source) {
        if (source.hasOwnProperty(key)) {
            target[key] = source[key];
        }
    }
    return target;
}

/**
 * @param {*} target