|  | // Copyright 2016 the V8 project authors. All rights reserved. | 
|  | // Use of this source code is governed by a BSD-style license that can be | 
|  | // found in the LICENSE file. | 
|  |  | 
|  | let compileCount = 0; | 
|  |  | 
|  | const Debug = new DebugWrapper(); | 
|  |  | 
|  | Debug.setListener(function(event, exec_state, event_data, data) { | 
|  | if (event != Debug.DebugEvent.AfterCompile) return; | 
|  | compileCount++; | 
|  | }); | 
|  |  | 
|  | Debug.enable(); | 
|  | assertTrue(compileCount != 0); | 
|  |  | 
|  | const compileCountAfterEnable = compileCount; | 
|  |  | 
|  | Debug.enable();  // Idempotent. | 
|  | assertEquals(compileCountAfterEnable, compileCount); | 
|  |  | 
|  | Debug.disable(); | 
|  | assertEquals(compileCountAfterEnable, compileCount); | 
|  |  | 
|  | Debug.disable();  // Idempotent. | 
|  | assertEquals(compileCountAfterEnable, compileCount); | 
|  |  | 
|  | Debug.enable();  // Re-enabling causes recompilation. | 
|  | assertEquals(2 * compileCountAfterEnable, compileCount); |