check if onListeners are set

apps/debugger/src/app/debugger-api.ts

@@ -119,17 +119,17 @@ export const DebuggerApiMixin = (Base) => class extends Base {
 
   debug (hash) {
     this.debugHash = hash
-    this.onDebugRequestedListener(hash)
+    if (this.onDebugRequestedListener) this.onDebugRequestedListener(hash)
   }
 
   onActivation () {
-    this.on('editor', 'breakpointCleared', (fileName, row) => this.onBreakpointClearedListener(fileName, row))
-    this.on('editor', 'breakpointAdded', (fileName, row) => this.onBreakpointAddedListener(fileName, row))
-    this.on('editor', 'contentChanged', () => this.onEditorContentChangedListener())  
+    this.on('editor', 'breakpointCleared', (fileName, row) => { if (this.onBreakpointClearedListener) this.onBreakpointClearedListener(fileName, row) })
+    this.on('editor', 'breakpointAdded', (fileName, row) => { if (this.onBreakpointAddedListener) this.onBreakpointAddedListener(fileName, row) })
+    this.on('editor', 'contentChanged', () => { if (this.onEditorContentChangedListener) this.onEditorContentChangedListener() })  
   }
 
   onDeactivation () {
-    this.onRemoveHighlightsListener()
+    if (this.onRemoveHighlightsListener) this.onRemoveHighlightsListener()
     this.off('editor', 'breakpointCleared')
     this.off('editor', 'breakpointAdded')
     this.off('editor', 'contentChanged')