创建一个在事件侦听器被触发时返回的函数

Question

In JavaScript, I have an event listener and I have a separate function that needs to return a value only when the listener is triggered.

Example of what I am looking for:

document.getElementById("myBtn").addEventListener("click", function(){ alert("Hello World!"); });



function test(){ 
//check if myBtn has been pressed then return 1;
//otherwise keep waiting and don't return anything until myBtn is clicked.
}

How can I do something like this?

Answer 1

var is_button_pressed = 0;

document.getElementById("myBtn").addEventListener("click", function(){ 
    is_button_pressed = 1;
});



 function test(){ 
    return is_button_pressed===1?1:undefined;
}

Answer 2

You could just use test() inside your original event listener and then for the event listener inside test(), use a closure to check the value of myBtn, and then return the value you want.

Honestly, I don't understand the point of 2 event listeners inside each other. For a RESTful request, why would you want to pause the request. You could just as simply capture the parameters of the request with the 1st button, and use the 2nd button to actually send the request. This is a lot easier to code and reason about.