// helper function to be able to change the event listener
function updateState() {
    states.search = this.value;
}

// checks if the pressed key equals to return key
function updateStateOnReturnKey(e) {
    if (e.keyCode === 13) {
        updateState.call(this);
    }
}

// removes the old event listener and applies the new one
function changeEvent(newEvent) {
    // remove the old listener
    switch (states.event) {
        case "onenterkey":
            this.removeEventListener("keyup", updateStateOnReturnKey);
            break;
        default:
            this.removeEventListener(states.event, updateState);
            break;
    }
    states.event = newEvent;
    // add the new listener
    switch (newEvent) {
        case "onenterkey":
            this.addEventListener("keyup", updateStateOnReturnKey);
            break;
        default:
            this.addEventListener(states.event, updateState);
            break;
    }
}

// updates the search field if the state does not match the value
function updateSearchInput(state) {
    if (this.value !== state) {
        this.value = state;
    }
}