Function defaults

libs/echarts/echarts-en.simple.js:427–436

* @param {*} target * @param {*} source * @param {boolean} [overlay=false] * @memberOf module:zrender/core/util

(target, source, overlay)

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

var createCanvas = function () {
    return methods.createCanvas();