将事件对象从事件处理程序传递到另一个函数

Question

Is it considered a bad practice to pass around event object from an event handler to some another function.

For example:

document.getElementById('something').addEventListener('mousedown', function(e) {
    console.log(someAnotherFunction(e));
});

I don't know why, but to me this looks like a code smell ?

Answer 1

Generally no, that is a perfectly fine pattern.

It is a good idea, though, to decouple event handling and application logic. So instead of this:

document.getElementById('something').addEventListener('mousedown', doStuff);

function doStuff(event) {
    var foo = event.target.getAttribute('foo');
    console.log("doing stuff with " + foo);
    doMagic(foo);
}

you would want to do that:

document.getElementById('something').addEventListener('mousedown', function (event) {
    var foo = event.target.getAttribute(foo);
    doStuff(foo);
});

function doStuff(foo) {
    console.log("doing stuff with " + foo);
    doMagic(foo);
}

(Not sure if this applies in your case, consider this more of a general comment.)