I have 2 functions. The second one is faster than the first one,how could the function wait to plete first one's work?

function1(); // slow 

function2(); // fast

I have 2 functions. The second one is faster than the first one,how could the function wait to plete first one's work?

function1(); // slow 

function2(); // fast

• javascript

Share Improve this question Follow edited Oct 27, 2012 at 12:15 Sibu 4,61722 gold badges2929 silver badges3838 bronze badges asked Oct 27, 2012 at 12:09 Dorukcan KişinDorukcan Kişin 1,13122 gold badges1414 silver badges2929 bronze badges

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4 Answers 4

Sorted by: Reset to default 4

JavaScript is imperative and single-threaded, it just works like this. function2() won't start until function1() finishes.

If by slow you mean calling asynchronously some external service via AJAX, then we're talking. function1() must provide some sort of callback so that when asynchronous request finishes, function2() is called:

function1(function2);

The implementation is trivial, e.g. using jQuery:

function function1(callback) {
  $.ajax({url: 'some-url'}).done(callback);
}

If functions are to be called asynchronously, aside from the obvious callback approach, their sequencing could be based on the events framework. You could add an event listener with function1 as a handler, and trigger that event within function2.

You must be using some AJAX request. So, after ajax plete call callback function like:

function1 = new function(callback) {
    $.ajax({...}).done(callback());
}

function1(function2);

If your calling one function after the other then it will finish the first either it may be slow or fast.