node/test/parallel/test-event-emitter-once.js
Rich Trott a180259e42 test,lib,doc: use function declarations
Replace function expressions with function declarations in preparation
for a lint rule requiring function declarations.

PR-URL: https://github.com/nodejs/node/pull/12711
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
2017-05-01 15:56:58 -07:00

58 lines
1.8 KiB
JavaScript

// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
'use strict';
const common = require('../common');
const assert = require('assert');
const EventEmitter = require('events');
const e = new EventEmitter();
e.once('hello', common.mustCall());
e.emit('hello', 'a', 'b');
e.emit('hello', 'a', 'b');
e.emit('hello', 'a', 'b');
e.emit('hello', 'a', 'b');
function remove() {
assert.fail('once->foo should not be emitted');
}
e.once('foo', remove);
e.removeListener('foo', remove);
e.emit('foo');
e.once('e', common.mustCall(function() {
e.emit('e');
}));
e.once('e', common.mustCall());
e.emit('e');
// Verify that the listener must be a function
assert.throws(() => {
const ee = new EventEmitter();
ee.once('foo', null);
}, /^TypeError: "listener" argument must be a function$/);