Can a getJSON url string be dynamically created?

Question

Is it possible to replace this approach for the url string:

    $.when($.getJSON(url0), $.getJSON(url1), $.getJSON(url2), $.getJSON(url3)).then(function() { ...

using another JSON file?

Why? The number of url items changes and I want to pull them from a single file without revising where this code lives each time. I could be dealing with url0-url3 or url0-40 then backto url0-url20.

The current approach forces a manual update of the array that's used to build the url string plus an update to the function.

What do you suggest?

Answer 1

Maybe something like this?

var urls = [
  'http://jsonplaceholder.typicode.com/posts/18',
  'http://jsonplaceholder.typicode.com/posts/37'
];

var results = {};

function saveResult(urlPath, data) {
  results[urlPath] = data;
}

function f() {
  ($.when).apply(this, Array.prototype.slice.call(arguments).map(function(urlPath) {
    return $.getJSON(urlPath, saveResult.bind(this, urlPath));
  })).then(function() {
   console.log('Completed fetch', results); 
  });
}

f.apply(this, urls);

UPDATE: If you want to grab the urls from a file, something like this should work:

function makeUrls(cb) {
  var urls = [];
  var idString1 = '???', idString2 = '????';
  $.when($.getJSON('new_name2.json')).then(function(c) {
    $.each(c.myStuff, function(f, e) {
      urls.push(idString1 + e.id + idString2);
    });
    cb(urls);
  });
}

var results = {};

function saveResult(urlPath, data) {
  results[urlPath] = data;
}

function f() {
  ($.when).apply(this, Array.prototype.slice.call(arguments).map(function(urlPath) {
    return $.getJSON(urlPath, saveResult.bind(this, urlPath));
  })).then(function() { console.log('DID IT!', results); });
}

makeUrls(function(urls) {
  f.apply(this, urls);
});