Array find方法在UC浏览器未定义

/*
*  findIndex (UCbrowser)
*/
if (![].findIndex) {
    Array.prototype.findIndex = function (predicate) {
        const array = this;
        for (let i = 0, value; i < array.length; i++) {
            value = array[i];
            if (predicate.apply(array, [value, i, array])) {
                return i;
            }
        }
        return -1;
    };
}

/*
*  find (UCbrowser)
*/
if (![].find) {
    Array.prototype.find = function (predicate) {
        return this[this.findIndex(predicate)];
    };
}