Loop to add data to complex JSON object - json

Question

I have a complex JSON Object like this:
var requestData = { __batchRequests: [ { __changeRequests: [
{ requestUri: "Customers", method: "POST", headers: { "Content-ID": "1" }, data: {
CustomerID: 400, CustomerName: "John"
} }
] } ] };
I am trying to do two things:
Declare this object but with the variable data empty
With a loop, add items dynamically to the data object,
How can I do it?

Answer 1

This isn't too complex an object. And it isn't JSON until it's converted into a string.
Right now, it's just plain-ol' JS objects and arrays.
Breaking that down into its elements might look like this:
var requestData = {};
requestData.__batchRequests = [];
requestData.__batchRequests[0] = {};
requestData.__batchRequests[0].__changeRequests = [];
requestData.__batchRequests[0].__changeRequests[0] = {};
requestData.__batchRequests[0].__changeRequests[0].requestUri = "Customers";
requestData.__batchRequests[0].__changeRequests[0].method = "POST";
requestData.__batchRequests[0].__changeRequests[0].headers = { "Content-ID" : "1" };
requestData.__batchRequests[0].__changeRequests[0].data = {};
Aside from the repeats, what do you see?
Personally, I see that __changeRequests[0] is an object as simple as:
var changeRequest = {
requestUri : "Customers",
method : "POST",
headers : { "Content-ID" : "1" },
data : {}
};
I also see that I can just push that onto my array of change requests:
requestData.__batchRequests[0].__changeRequests.push(changeRequest);
Right?
I also know that my changeRequest variable still points to the one that I just added to the array, and whatever I change on the object will show up as changed in the array's reference to the object, too:
changeRequest.data.CustomerName = "Bob";
changeRequest.data.CustomerID = "204";
requestData.__/*...*/changeRequests[0].data.CustomerName; // Bob
So how about writing yourself some helper-functions?
function extend (obj, additions) {
var key;
for (key in obj) { if (additions.hasOwnProperty(key)) {
obj[key] = additions[key];
}
}
function makeChangeRequest (url, method, headers, data) {
var request = {
requestUri : url,
method : method,
headers : {},
data : {}
};
extend(request.headers, headers);
extend(request.data, data);
return request;
}
function getBatch (num) { return requestData.__batchRequests[num]; }
var changeReq = makeChangeRequest("Customers",
"POST",
{ "Content-ID" : "1" },
{ CustomerName : "Bob", CustomerID : "2012" });
var batch = getBatch(0);
batch.__changeRequests.push(changeReq);
If you want to add more data to changeReq.data later:
extend(changeReq.data, { Address : "33 Nowhere Rd.", City : "Splitsville" });

Answer 2

For the first part of your question, you can initialize data with an empty associative array:
var requestData = { __batchRequests: [ { __changeRequests: [
{ requestUri: "Customers", method: "POST", headers: { "Content-ID": "1" }, data: {} }
] } ] };
This next part assumes, perhaps incorrectly, that you can use jQuery. It also assumes that you have an array containing all of the relevant key value pairs.
var customerDeetsArray =[{CustomerID: 400}, {CustomerName: "John"}];
for (var i in customerDeetsArray) {
requestData.data = $.extend(requestData.data, customerDeetsArray[i]);
}
See working example which makes use of console.debug:
http://jsfiddle.net/4Rh72/6/