JavaScript questions that don't deserve their own thread

/**
 * Checks whether a key was just released.
 * @param {String} keyName The mapped name of the key
 * @returns {Number} If the key was just released, the amount of frames it was held for. 0 otherwise.
 */
Input.isReleased = function (keyName) {
    if (this._justReleased.includes(keyName)) return Graphics.frameCount - this._pressedStartTimes[keyName];
    else return 0;
}

void ((alias) => {
    Input.initialize = function () {
        alias.call(this);
        this._pressedStartTimes = {};
    }
})(Input.initialize);

Input.update = function () {
    this._pollGamepads();
    this._justReleased = [];
    if (this._currentState[this._latestButton]) {
        this._pressedTime++;
    } else {
        this._latestButton = null;
    }
    for (var name in this._currentState) {
        if (this._currentState[name] && !this._previousState[name]) {
            this._latestButton = name;
            this._pressedTime = 0;
            this._date = Date.now();
            this._pressedStartTimes[name] = Graphics.frameCount;
        } else if (!this._currentState[name] && this._previousState[name]) {
            this._justReleased.push(name);
        }
        this._previousState[name] = this._currentState[name];
    }
    this._updateDirection();
};