Add end method to d3 transition (#39355)

types/d3-transition/d3-transition-tests.ts

@@ -421,6 +421,9 @@ if (listener) {
 // remove listener
 enterTransition = enterTransition.on('end', null); // check chaining return type by re-assigning
 
+// check end method exists
+enterTransition.end();
+
 // --------------------------------------------------------------------------
 // Test Control Flow
 // --------------------------------------------------------------------------

types/d3-transition/index.d.ts

@@ -456,6 +456,11 @@ export interface Transition<GElement extends BaseType, Datum, PElement extends B
      */
     on(type: string, listener: ValueFn<GElement, Datum, void>): this;
 
+    /**
+     * Returns a promise that resolves when every selected element finishes transitioning. If any element’s transition is cancelled or interrupted, the promise rejects.
+     */
+    end(): Promise<void>;
+
     // Control Flow ----------------------
 
     /**