Initial support for dynamic properties

lib/browser/api/browser-window.js

@@ -138,6 +138,8 @@ BrowserWindow.prototype._init = function () {
       this._touchBar.emit('interaction', id, details)
     }
   })
+
+  this._touchBarListener = this._refreshTouchBarItem.bind(this)
 }
 
 BrowserWindow.getFocusedWindow = () => {
@@ -208,8 +210,11 @@ Object.assign(BrowserWindow.prototype, {
 // TouchBar API
 BrowserWindow.prototype.setTouchBar = function (touchBar) {
   if (touchBar == null) {
+    if (this._touchBar != null) {
+      this._touchBar.removeListener('change', this._touchBarListener)
+      this._touchBar = null
+    }
     this._destroyTouchBar()
-    this._touchBar = null
     return
   }
 
@@ -218,11 +223,8 @@ BrowserWindow.prototype.setTouchBar = function (touchBar) {
   }
 
   this._touchBar = touchBar
+  this._touchBar.on('change', this._touchBarListener)
   this._setTouchBar(touchBar.ordereredItems)
 }
 
-BrowserWindow.prototype._updateTouchBarItem = function (itemID) {
-  this._refreshTouchBarItem(itemID)
-}
-
 module.exports = BrowserWindow

lib/browser/api/touch-bar.js

@@ -14,6 +14,9 @@ class TouchBar extends EventEmitter {
     this.ordereredItems = []
     const registerItem = (item) => {
       this.items[item.id] = item
+      item.on('change', () => {
+        this.emit('change', item.id, item.type)
+      })
       if (item.child instanceof TouchBar) {
         item.child.ordereredItems.forEach(registerItem)
       }
@@ -35,8 +38,9 @@ class TouchBar extends EventEmitter {
   }
 }
 
-class TouchBarItem {
+class TouchBarItem extends EventEmitter {
   constructor (config) {
+    super()
     this.id = `${itemIdIncrementor++}`
   }
 }
@@ -81,7 +85,16 @@ TouchBar.Label = class TouchBarLabel extends TouchBarItem {
   constructor (config) {
     super(config)
     this.type = 'label'
-    this.label = config.label
+    this._label = config.label
+  }
+
+  set label (newLabel) {
+    this._label = newLabel
+    this.emit('change')
+  }
+
+  get label () {
+    return this._label
   }
 }