test: refactor large event emitter tests

test/parallel/test-event-emitter-listeners.js

@@ -1,32 +1,38 @@
 'use strict';
 
 require('../common');
-var assert = require('assert');
-var events = require('events');
+const assert = require('assert');
+const events = require('events');
 
 function listener() {}
 function listener2() {}
 
-var e1 = new events.EventEmitter();
-e1.on('foo', listener);
-var fooListeners = e1.listeners('foo');
-assert.deepStrictEqual(e1.listeners('foo'), [listener]);
-e1.removeAllListeners('foo');
-assert.deepStrictEqual(e1.listeners('foo'), []);
-assert.deepStrictEqual(fooListeners, [listener]);
+{
+  const ee = new events.EventEmitter();
+  ee.on('foo', listener);
+  const fooListeners = ee.listeners('foo');
+  assert.deepStrictEqual(ee.listeners('foo'), [listener]);
+  ee.removeAllListeners('foo');
+  assert.deepStrictEqual(ee.listeners('foo'), []);
+  assert.deepStrictEqual(fooListeners, [listener]);
+}
 
-var e2 = new events.EventEmitter();
-e2.on('foo', listener);
-var e2ListenersCopy = e2.listeners('foo');
-assert.deepStrictEqual(e2ListenersCopy, [listener]);
-assert.deepStrictEqual(e2.listeners('foo'), [listener]);
-e2ListenersCopy.push(listener2);
-assert.deepStrictEqual(e2.listeners('foo'), [listener]);
-assert.deepStrictEqual(e2ListenersCopy, [listener, listener2]);
+{
+  const ee = new events.EventEmitter();
+  ee.on('foo', listener);
+  const eeListenersCopy = ee.listeners('foo');
+  assert.deepStrictEqual(eeListenersCopy, [listener]);
+  assert.deepStrictEqual(ee.listeners('foo'), [listener]);
+  eeListenersCopy.push(listener2);
+  assert.deepStrictEqual(ee.listeners('foo'), [listener]);
+  assert.deepStrictEqual(eeListenersCopy, [listener, listener2]);
+}
 
-var e3 = new events.EventEmitter();
-e3.on('foo', listener);
-var e3ListenersCopy = e3.listeners('foo');
-e3.on('foo', listener2);
-assert.deepStrictEqual(e3.listeners('foo'), [listener, listener2]);
-assert.deepStrictEqual(e3ListenersCopy, [listener]);
+{
+  const ee = new events.EventEmitter();
+  ee.on('foo', listener);
+  const eeListenersCopy = ee.listeners('foo');
+  ee.on('foo', listener2);
+  assert.deepStrictEqual(ee.listeners('foo'), [listener, listener2]);
+  assert.deepStrictEqual(eeListenersCopy, [listener]);
+}

test/parallel/test-event-emitter-remove-all-listeners.js

@@ -1,11 +1,11 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
-var events = require('events');
+const common = require('../common');
+const assert = require('assert');
+const events = require('events');
 
 
 function expect(expected) {
-  var actual = [];
+  const actual = [];
   process.on('exit', function() {
     assert.deepStrictEqual(actual.sort(), expected.sort());
   });
@@ -17,56 +17,63 @@ function expect(expected) {
 
 function listener() {}
 
-var e1 = new events.EventEmitter();
-e1.on('foo', listener);
-e1.on('bar', listener);
-e1.on('baz', listener);
-e1.on('baz', listener);
-var fooListeners = e1.listeners('foo');
-var barListeners = e1.listeners('bar');
-var bazListeners = e1.listeners('baz');
-e1.on('removeListener', expect(['bar', 'baz', 'baz']));
-e1.removeAllListeners('bar');
-e1.removeAllListeners('baz');
-assert.deepStrictEqual(e1.listeners('foo'), [listener]);
-assert.deepStrictEqual(e1.listeners('bar'), []);
-assert.deepStrictEqual(e1.listeners('baz'), []);
-// after calling removeAllListeners,
-// the old listeners array should stay unchanged
-assert.deepStrictEqual(fooListeners, [listener]);
-assert.deepStrictEqual(barListeners, [listener]);
-assert.deepStrictEqual(bazListeners, [listener, listener]);
-// after calling removeAllListeners,
-// new listeners arrays are different from the old
-assert.notEqual(e1.listeners('bar'), barListeners);
-assert.notEqual(e1.listeners('baz'), bazListeners);
+{
+  const ee = new events.EventEmitter();
+  ee.on('foo', listener);
+  ee.on('bar', listener);
+  ee.on('baz', listener);
+  ee.on('baz', listener);
+  const fooListeners = ee.listeners('foo');
+  const barListeners = ee.listeners('bar');
+  const bazListeners = ee.listeners('baz');
+  ee.on('removeListener', expect(['bar', 'baz', 'baz']));
+  ee.removeAllListeners('bar');
+  ee.removeAllListeners('baz');
+  assert.deepStrictEqual(ee.listeners('foo'), [listener]);
+  assert.deepStrictEqual(ee.listeners('bar'), []);
+  assert.deepStrictEqual(ee.listeners('baz'), []);
+  // After calling removeAllListeners(),
+  // the old listeners array should stay unchanged.
+  assert.deepStrictEqual(fooListeners, [listener]);
+  assert.deepStrictEqual(barListeners, [listener]);
+  assert.deepStrictEqual(bazListeners, [listener, listener]);
+  // After calling removeAllListeners(),
+  // new listeners arrays is different from the old.
+  assert.notEqual(ee.listeners('bar'), barListeners);
+  assert.notEqual(ee.listeners('baz'), bazListeners);
+}
 
-var e2 = new events.EventEmitter();
-e2.on('foo', listener);
-e2.on('bar', listener);
-// expect LIFO order
-e2.on('removeListener', expect(['foo', 'bar', 'removeListener']));
-e2.on('removeListener', expect(['foo', 'bar']));
-e2.removeAllListeners();
-console.error(e2);
-assert.deepStrictEqual([], e2.listeners('foo'));
-assert.deepStrictEqual([], e2.listeners('bar'));
+{
+  const ee = new events.EventEmitter();
+  ee.on('foo', listener);
+  ee.on('bar', listener);
+  // Expect LIFO order
+  ee.on('removeListener', expect(['foo', 'bar', 'removeListener']));
+  ee.on('removeListener', expect(['foo', 'bar']));
+  ee.removeAllListeners();
+  assert.deepStrictEqual([], ee.listeners('foo'));
+  assert.deepStrictEqual([], ee.listeners('bar'));
+}
 
-var e3 = new events.EventEmitter();
-e3.on('removeListener', listener);
-// check for regression where removeAllListeners throws when
-// there exists a removeListener listener, but there exists
-// no listeners for the provided event type
-assert.doesNotThrow(e3.removeAllListeners.bind(e3, 'foo'));
+{
+  const ee = new events.EventEmitter();
+  ee.on('removeListener', listener);
+  // Check for regression where removeAllListeners() throws when
+  // there exists a 'removeListener' listener, but there exists
+  // no listeners for the provided event type.
+  assert.doesNotThrow(ee.removeAllListeners.bind(ee, 'foo'));
+}
 
-var e4 = new events.EventEmitter();
-var expectLength = 2;
-e4.on('removeListener', function(name, listener) {
-  assert.equal(expectLength--, this.listeners('baz').length);
-});
-e4.on('baz', function() {});
-e4.on('baz', function() {});
-e4.on('baz', function() {});
-assert.equal(e4.listeners('baz').length, expectLength + 1);
-e4.removeAllListeners('baz');
-assert.equal(e4.listeners('baz').length, 0);
+{
+  const ee = new events.EventEmitter();
+  var expectLength = 2;
+  ee.on('removeListener', function(name, listener) {
+    assert.strictEqual(expectLength--, this.listeners('baz').length);
+  });
+  ee.on('baz', function() {});
+  ee.on('baz', function() {});
+  ee.on('baz', function() {});
+  assert.strictEqual(ee.listeners('baz').length, expectLength + 1);
+  ee.removeAllListeners('baz');
+  assert.strictEqual(ee.listeners('baz').length, 0);
+}