JavaScript中的字典

Currently I tried to reform my JSON data to a dictionary to store only needed data in an array with key and value.

* Edit to put my full code. *

This is how I do:

var myData = [];
var urlPath = "https://tipjira.pgdev.abcd.com/rest/api/2/search?jql=project=GRIFR14%2Band%2BfixVersion=15018";
var jiraMapping = [];

$.ajax({
    url : "http://frparwself22.dhcp.par.abcd.com:8080/jiraproxy/jira?url=" + urlPath,
    dataType : 'json',
    type: 'GET',

    success : function(data) {
        for (var i=0; i<data.issues.length; i++) {
            var obj = {};
            obj[data.issues[i].key] = data.issues[i].self;
            jiraMapping.push(obj);      
            alert(jiraMapping.length);
        }
    },
    error : function() {
        alert("Error!")
    }
});

alert(jiraMapping.length);

My original data is {issues:[{...,"self":"/rest/api/2/issue/175074","key":"GRIFR14-36",...}, {...,"self":"/rest/api/2/issue/175075","key":"GRIFR14-37",...}, ...]}. And I want to reform to have the array with key and value which are key and self.

So the data in my jiraMapping should be something like [{k1:v1}, {k2,v2}, ...]. But when I tired to print the length of jiraMapping, the length is 0. I tried to put alert to check key and value that I add to the array and the values exist.

I don't know where is the problem exactly. Please help...

Without knowing exactly what information you're passing in, it's hard to say what's going wrong. That being said, my first guess is that data/myData isn't formatted the way you think. For instance, if myData.issues.length is 0, nothing in the loop will get executed.

There's also a chance that you're never actually running the success function. Could you post some more code?

The problem lies in the data that you are receiving or you have a typo somewhere later when checking length. This all looks fine, and I tried to replicate your problem like this:

var jiraMapping = [];    
var myData = [{"A":"a"},{"B":"b"}];
for (var i=0; i<myData.length; i++) {
var obj = {};
obj[myData[i]] = myData[i];
jiraMapping.push(obj);    
}
console.log(jiraMapping);

but this works fine, fiddle here: http://jsfiddle.net/GWpBs/2/