Implemented a simple eventbus

Jakefile.js

@@ -17,7 +17,7 @@ var VIS_MIN = './vis.min.js';
  * default task
  */
 desc('Execute all tasks: build all libraries');
-task('default', ['build', 'minify'], function () {
+task('default', ['build', 'minify', 'test'], function () {
     console.log('done');
 });
 
@@ -50,6 +50,7 @@ task('build', {async: true}, function () {
             './src/dataset.js',
             './src/stack.js',
             './src/range.js',
+            './src/eventbus.js',
             './src/controller.js',
 
             './src/component/component.js',
@@ -113,6 +114,25 @@ task('minify', function () {
     console.log('created ' + VIS_MIN);
 });
 
+/**
+ * test task
+ */
+desc('Test the library');
+task('test', ['build'], function () {
+    // TODO: use a testing suite for testing: nodeunit, mocha, tap, ...
+    var filelist = new jake.FileList();
+    filelist.include([
+        './test/**/*.js'
+    ]);
+
+    var files = filelist.toArray();
+    files.forEach(function (file) {
+        require('./' + file);
+    });
+
+    console.log('Executed ' + files.length + ' test files successfully');
+});
+
 /**
  * replace version, date, and name placeholders in the provided file
  * @param {String} filename

package.json

@@ -21,7 +21,8 @@
         "browser"
     ],
     "scripts": {
-        "prepublish": "jake"
+        "prepublish": "jake",
+        "test": "jake test --trace"
     },
     "dependencies": {},
     "devDependencies": {

src/eventbus.js

@@ -0,0 +1,64 @@
+/**
+ * An event bus can be used to emit events, and to subscribe to events
+ * @constructor EventBus
+ */
+function EventBus() {
+    this.subscriptions = [];
+}
+
+/**
+ * Subscribe to an event
+ * @param {String | RegExp} event   The event can be a regular expression, or
+ *                                  a string with wildcards, like 'server.*'.
+ * @param {function} callback.      Callback are called with three parameters:
+ *                                  {String} event, {Object} [data],
+ *                                  {*} [source]
+ * @param {*} [target]
+ * @returns {String} id    A subscription id
+ */
+EventBus.prototype.on = function (event, callback, target) {
+    var subscription = {
+        id:       util.randomUUID(),
+        event:    event instanceof RegExp ? event : new RegExp(event.replace('*', '\\w+')),
+        callback: (typeof callback === 'function') ? callback : null,
+        target:   target
+    };
+
+    this.subscriptions.push(subscription);
+
+    return subscription.id;
+};
+
+/**
+ * Unsubscribe from an event
+ * @param {String} id   subscription id
+ */
+EventBus.prototype.off = function (id) {
+    var i = 0;
+    while (i < this.subscriptions.length) {
+        var subscription = this.subscriptions[i];
+        if (subscription.id == id) {
+            this.subscriptions.splice(i, 1);
+        }
+        else {
+            i++;
+        }
+    }
+};
+
+/**
+ * Emit an event
+ * @param {String} event
+ * @param {Object} [data]
+ * @param {*} [source]
+ */
+EventBus.prototype.emit = function (event, data, source) {
+    for (var i =0; i < this.subscriptions.length; i++) {
+        var subscription = this.subscriptions[i];
+        if (subscription.event.test(event)) {
+            if (subscription.callback) {
+                subscription.callback(event, data, source);
+            }
+        }
+    }
+};

src/module/exports.js

@@ -10,6 +10,7 @@ var vis = {
     Range: Range,
     Stack: Stack,
     TimeStep: TimeStep,
+    EventBus: EventBus,
 
     components: {
         items: {

src/util.js

@@ -597,9 +597,13 @@ util.option.asElement = function (value, defaultValue) {
  * @param {String} css    Text containing css
  */
 util.loadCss = function (css) {
+    if (typeof document === 'undefined') {
+        return;
+    }
+
     // get the script location, and built the css file name from the js file name
     // http://stackoverflow.com/a/2161748/1262753
-    var scripts = document.getElementsByTagName('script');
+    // var scripts = document.getElementsByTagName('script');
     // var jsFile = scripts[scripts.length-1].src.split('?')[0];
     // var cssFile = jsFile.substring(0, jsFile.length - 2) + 'css';
 

test/eventbus.js

@@ -0,0 +1,38 @@
+// test vis.EventBus
+
+var assert = require('assert'),
+    vis = require('../vis');
+
+var bus = new vis.EventBus();
+
+var received = [];
+
+var id1 = '1';
+bus.on('message', function (event, data, source) {
+    received.push({
+        event: event,
+        data: data,
+        source: source
+    });
+}, id1);
+
+var id2 = '2';
+bus.emit('message', {text: 'hello world'}, id2);
+bus.on('chat:*', function (event, data, source) {
+    received.push({
+        event: event,
+        data: data,
+        source: source
+    });
+});
+
+bus.emit('chat:1', null, id2);
+bus.emit('chat:2', {text: 'hello world'}, id1);
+
+// verify if the messages are received
+assert.deepEqual(received, [
+    {event: 'message', data: {text: 'hello world'}, source: id2},
+    {event: 'chat:1', data: null, source: id2},
+    {event: 'chat:2', data: {text: 'hello world'}, source: id1}
+]);
+

vis.js

@@ -628,9 +628,13 @@ util.option.asElement = function (value, defaultValue) {
  * @param {String} css    Text containing css
  */
 util.loadCss = function (css) {
+    if (typeof document === 'undefined') {
+        return;
+    }
+
     // get the script location, and built the css file name from the js file name
     // http://stackoverflow.com/a/2161748/1262753
-    var scripts = document.getElementsByTagName('script');
+    // var scripts = document.getElementsByTagName('script');
     // var jsFile = scripts[scripts.length-1].src.split('?')[0];
     // var cssFile = jsFile.substring(0, jsFile.length - 2) + 'css';
 
@@ -2634,6 +2638,71 @@ Range.prototype.move = function(moveFactor) {
     this.end = newEnd;
 };
 
+/**
+ * An event bus can be used to emit events, and to subscribe to events
+ * @constructor EventBus
+ */
+function EventBus() {
+    this.subscriptions = [];
+}
+
+/**
+ * Subscribe to an event
+ * @param {String | RegExp} event   The event can be a regular expression, or
+ *                                  a string with wildcards, like 'server.*'.
+ * @param {function} callback.      Callback are called with three parameters:
+ *                                  {String} event, {Object} [data],
+ *                                  {*} [source]
+ * @param {*} [target]
+ * @returns {String} id    A subscription id
+ */
+EventBus.prototype.on = function (event, callback, target) {
+    var subscription = {
+        id:       util.randomUUID(),
+        event:    event instanceof RegExp ? event : new RegExp(event.replace('*', '\\w+')),
+        callback: (typeof callback === 'function') ? callback : null,
+        target:   target
+    };
+
+    this.subscriptions.push(subscription);
+
+    return subscription.id;
+};
+
+/**
+ * Unsubscribe from an event
+ * @param {String} id   subscription id
+ */
+EventBus.prototype.off = function (id) {
+    var i = 0;
+    while (i < this.subscriptions.length) {
+        var subscription = this.subscriptions[i];
+        if (subscription.id == id) {
+            this.subscriptions.splice(i, 1);
+        }
+        else {
+            i++;
+        }
+    }
+};
+
+/**
+ * Emit an event
+ * @param {String} event
+ * @param {Object} [data]
+ * @param {*} [source]
+ */
+EventBus.prototype.emit = function (event, data, source) {
+    for (var i =0; i < this.subscriptions.length; i++) {
+        var subscription = this.subscriptions[i];
+        if (subscription.event.test(event)) {
+            if (subscription.callback) {
+                subscription.callback(event, data, source);
+            }
+        }
+    }
+};
+
 /**
  * @constructor Controller
  *
@@ -5112,6 +5181,7 @@ var vis = {
     Range: Range,
     Stack: Stack,
     TimeStep: TimeStep,
+    EventBus: EventBus,
 
     components: {
         items: {