如何改进我的代码来实现'return false'？

Question

I am trying to return false after a conditional statement fail.

I have

$('#btn').click(function() {
    $('.title').each(function() {
        if (id == $(this).attr('id')) {
            alert('The name already exists.')
            return false; //I hope my codes would stop here if condition is true
        }
    })
    // my codes still call the doSomething function even if the conditional         
    //statement is true
    doSomething();
})​

I want do call the doSomething function ONLY if id != $(this).attr('id).

The codes below gave me what I want but it seems ugly.

$('#btn').click(function() {
    var nameExist = false
    $('.title').each(function() {
        if (id == $(this).attr('id')) {
            alert('The name already exists.')
            nameExist = true;
            return false; //I hope my codes would stop here if condition is true
        }
    })
    if (!nameExist) {
        doSomething();
    }
})​

Anyone has a better approach for this? Thanks a lot!

Answer 1

Switch to a basic for loop.

$('#btn').click(function() {
    var elements = $(".title");
    for (var i = 0; i < elements.length; i++) {
        if (id == elements[i].id) {
            alert('The name already exists.')
            return false; //I hope my codes would stop here if condition is true
        }
    }

    doSomething();
})​

Answer 2

You don't need to iterate thrue the elements , you can get it by the id and class like, #myId.myClass .

$('#btn').click(function() {
    if($('#' + id + '.title').length) {
        alert('The name already exists.');
    } else {
        doSomething();
    }
});

Answer 3

If you don't mind not exiting the loop early, you can use jQuery filter

$('#btn').click(function(){
    var itensWithSameName = $('.title').filter(function(){
      return id == $(this).attr('id');
    })

    if(itensWithSameName.size() > 0)
        alert('The name already exists.');
});

Answer 4

I think what you have is fine, but this avoids the extra conditional:

var func = doSomething;
...
if (id == $(this).attr('id')) {
   func = $.noop;
...

func();