setEventListener supports adding multiple event listeners.

Author: ethan-vanderheijden

src/model/Node.ts

@@ -23,7 +23,7 @@ export abstract class Node {
     /** @internal */
     protected _visible: boolean;
     /** @internal */
-    protected _listeners: Record<string, (params: any) => void>;
+    protected _listeners: Record<string, ((params: any) => void)[]>;
     /** @internal */
     protected _dirty: boolean = false;
     /** @internal */
@@ -83,14 +83,38 @@ export abstract class Node {
             return Orientation.flip(this._parent.getOrientation());
         }
     }
-
-    // event can be: resize, visibility, maximize (on tabset), close
-    setEventListener(event: string, callback: (params: any) => void) {
-        this._listeners[event] = callback;
+    
+    /**
+     * Adds the given event listener. Can optionally replace existing listeners.
+     * @param event valid events: resize, visibility, maximize (on tabset), close
+     * @param callback
+     * @param replace if set to true, existing listeners will be cleared
+     */
+    setEventListener(event: string, callback: (params: any) => void, replace:boolean=true) {
+        if (replace || this._listeners[event] === undefined) {
+            this._listeners[event] = [callback];
+        } else {
+            this._listeners[event].push(callback);
+        }
     }
 
-    removeEventListener(event: string) {
-        delete this._listeners[event];
+    /**
+     * If a callback is provided, it will be removed from the event.
+     * If no callback is provided, all callbacks will be removed from the event.
+     * @param event valid events: resize, visibility, maximize (on tabset), close
+     * @param callback the specific callback to remove
+     */
+    removeEventListener(event: string, callback?: (params: any) => void) {
+        if (callback) {
+            if (this._listeners[event] !== undefined) {
+                const index = this._listeners[event].indexOf(callback);
+                if (index !== -1) {
+                    this._listeners[event].splice(index, 1);
+                }
+            }
+        } else {
+            this._listeners[event] = [];
+        }
     }
 
     abstract toJson(): IJsonRowNode | IJsonBorderNode | IJsonTabSetNode | IJsonTabNode | undefined;
@@ -104,7 +128,9 @@ export abstract class Node {
     _fireEvent(event: string, params: any) {
         // console.log(this._type, " fireEvent " + event + " " + JSON.stringify(params));
         if (this._listeners[event] !== undefined) {
-            this._listeners[event](params);
+            for(const callback of this._listeners[event]) {
+                callback(params);
+            }
         }
     }
 

test/Model.test.ts

@@ -504,17 +504,32 @@ describe("Tree", function () {
         });
 
         it("close tab", () => {
-            let closed = false;
-            tab("/ts0/t0").setEventListener("close", () => { closed = true; })
+            let closed1 = false;
+            let closed2 = false;
+            let closed3 = false;
+            let closed4 = false;
+            tab("/ts0/t0").setEventListener("close", () => { closed1 = true; }, false);
+            tab("/ts0/t0").setEventListener("close", () => { closed2 = true; });
+            tab("/ts0/t0").setEventListener("close", () => { closed3 = true; }, false);
+            const close4Callback = () => { closed4 = true; }
+            tab("/ts0/t0").setEventListener("close", close4Callback, false);
+            tab("/ts0/t0").removeEventListener("close", close4Callback);
             doAction(Actions.deleteTab(tab("/ts0/t0").getId()));
-            expect(closed).equals(true);
+            expect(closed1).equals(false);
+            expect(closed2).equals(true);
+            expect(closed3).equals(true);
+            expect(closed4).equals(false);
         });
 
         it("save tab", () => {
-            let saved = false;
-            tab("/ts0/t0").setEventListener("save", () => { saved = true; })
+            let saved1 = false;
+            let saved2 = false;
+            tab("/ts0/t0").setEventListener("save", () => { saved1 = true; });
+            tab("/ts0/t0").removeEventListener("save");
+            tab("/ts0/t0").setEventListener("save", () => { saved2 = true; }, false);
             model.toJson();
-            expect(saved).equals(true);
+            expect(saved1).equals(false);
+            expect(saved2).equals(true);
         });
 
         it("visibility tab", () => {