Function isString

libs/echarts/echarts.simple.js:684–686

* @memberOf module:zrender/core/util * @param {*} value * @return {boolean}

(value)

 * @return {boolean}
 */
function isString(value) {
    return objToString.call(value) === '[object String]';
}

/**
 * @memberOf module:zrender/core/util