node/test/parallel/test-event-emitter-listener-count.js

'use strict';

require('../common');
const assert = require('assert');
const EventEmitter = require('events');

const emitter = new EventEmitter();
emitter.on('foo', () => {});
emitter.on('foo', () => {});
emitter.on('baz', () => {});
// Allow any type
emitter.on(123, () => {});

assert.strictEqual(EventEmitter.listenerCount(emitter, 'foo'), 2);
assert.strictEqual(emitter.listenerCount('foo'), 2);
assert.strictEqual(emitter.listenerCount('bar'), 0);
assert.strictEqual(emitter.listenerCount('baz'), 1);
assert.strictEqual(emitter.listenerCount(123), 1);