Bug 921202 - Implement sdk/ui/id

lib/sdk/ui/id.js

@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+'use strict';
+
+module.metadata = {
+  'stability': 'experimental'
+};
+
+const method = require('method/core');
+const { uuid } = require('../util/uuid');
+
+const identified = new WeakMap();
+
+let identify = method('identify');
+identify.define(function(thing) {
+  if (!thing) {
+    return uuid();
+  }
+
+  if (!identified.has(thing)) {
+    identified.set(thing, uuid());
+  }
+
+  return identified.get(thing);
+});
+exports.identify = identify;

test/test-ui-id.js

@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+const { identify } = require('sdk/ui/id');
+const { Class } = require('sdk/core/heritage');
+
+const signature = /{[0-9a-f\-]+}/;
+
+exports['test generate id'] = function(assert) {
+  let first = identify();
+  let second = identify({});
+
+  assert.ok(signature.test(first), 'first id has a correct signature');
+  assert.ok(signature.test(second), 'second id has a correct signature');
+
+  assert.notEqual(first, identify(), 'identify generated new uuid [1]');
+  assert.notEqual(first, second, 'identify generated new uuid [2]');
+};
+
+exports['test get id'] = function(assert) {
+  let thing = {};
+  let thingID = identify(thing);
+
+  assert.equal(thingID, identify(thing), 'ids for things are cached by default');
+  assert.notEqual(identify(thing), identify({}), 'new ids for new things');
+};
+
+exports['test custom id definition for classes'] = function(assert) {
+  let Thing = Class({});
+  let thing = Thing();
+  let counter = 0;
+
+  identify.define(Thing, function(thing) {
+    return ++counter;
+  });
+
+  assert.equal(identify(thing), counter, 'it is possible to define custom identifications');
+  assert.ok(signature.test(identify({})), 'defining a custom identification does not affect the default behavior');
+}
+
+require('sdk/test').run(exports);