I'm trying to grasp deferred objects in jquery but keep running in trouble. Basically I have a series of functions I want to run where the result from function 1 dictates the logic in a second function.

I'm not sure if I have to invoke a pipe method somewhere or just use then() but either way I keep failing. If you look at the first function there is a object named data which is I want to pass to the second.

 function run() {
    var data1 = {};
    var data2 = {};

    var body = $('body');

    $.when(first()).then(second()).done(constructData);

    function first() {
        var d = new $.Deferred();



        var data = {} //arbitrary data set that i want to send to second

        data.message = 'first message';
        data.id = 1234;

        body.append('First done');

        //return data object? add it to the resolve method?
       d.resolve();
    }

    function second(data) { //how do I get this data object?

        var d = new $.Deferred();


        body.append('Data from first:');

         body.append('Second done');

        d.resolve();
    }
    function constructData() {

    }

}

I'm trying to grasp deferred objects in jquery but keep running in trouble. Basically I have a series of functions I want to run where the result from function 1 dictates the logic in a second function.

I'm not sure if I have to invoke a pipe method somewhere or just use then() but either way I keep failing. If you look at the first function there is a object named data which is I want to pass to the second.

 function run() {
    var data1 = {};
    var data2 = {};

    var body = $('body');

    $.when(first()).then(second()).done(constructData);

    function first() {
        var d = new $.Deferred();



        var data = {} //arbitrary data set that i want to send to second

        data.message = 'first message';
        data.id = 1234;

        body.append('First done');

        //return data object? add it to the resolve method?
       d.resolve();
    }

    function second(data) { //how do I get this data object?

        var d = new $.Deferred();


        body.append('Data from first:');

         body.append('Second done');

        d.resolve();
    }
    function constructData() {

    }

}

• javascript
• jquery
• jquery-deferred
• deferred

1 Answer 1

Here is a simplified, live demo of your example: http://jsfiddle/L96cD/

What is missing in your code:

1/ you need to pass in resolve the argument for the second function:

d.resolve(data);

2/ you need to return the deferred:

return d;

Note: in practice you would return the deferred before it is resolved (hence the name). Also, the deferred is built in some methods like ajax calls.