GitHub Repo File Structure Crawler

crawler.js

var ajax = function (url, callback) {
	var xhr = new XMLHttpRequest();
	xhr.open('GET', url, true);
	xhr.send();
	xhr.onreadystatechange = function (e) {
		if (e.target.status === 200 && e.target.readyState === 4) {
			callback(JSON.parse(e.target.response));
		}
	};
};

var buildGithubTree = function (user, repo) {

	var self = this;

	this.struct = [];

	this.addBranch = function (array, item) {
		ajax(item._links.self, function (data) {
			self.processTree(array, data);
		});
	};

	this.processTree = function (array, items) {

		var item, i;

		for (i = 0; i < items.length; i++) {
			item = items[i];

			if (item.type === 'dir') {
				array[i] = {folder : []};
				this.addBranch(array[i].folder, item);
			} else {
				array[i] = {item : item};
			}

		}

	};

	ajax('https://api.github.com/repos/' + user + '/' + repo + '/contents/', function (data) {
		self.processTree(self.struct, data);
	});

};