Update to Node.js 8 events API

tests/add-listeners.js

@@ -19,45 +19,93 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+var common = require('./common');
 var assert = require('assert');
-var events = require('../');
+var EventEmitter = require('../');
 
-var e = new events.EventEmitter();
+{
+  var ee = new EventEmitter();
+  var events_new_listener_emitted = [];
+  var listeners_new_listener_emitted = [];
 
-var events_new_listener_emited = [];
-var listeners_new_listener_emited = [];
-var times_hello_emited = 0;
+  // Sanity check
+  assert.strictEqual(ee.addListener, ee.on);
 
-// sanity check
-assert.equal(e.addListener, e.on);
+  ee.on('newListener', function(event, listener) {
+    // Don't track newListener listeners.
+    if (event === 'newListener')
+      return;
 
-e.on('newListener', function(event, listener) {
-  console.log('newListener: ' + event);
-  events_new_listener_emited.push(event);
-  listeners_new_listener_emited.push(listener);
-});
+    events_new_listener_emitted.push(event);
+    listeners_new_listener_emitted.push(listener);
+  });
 
-function hello(a, b) {
-  console.log('hello');
-  times_hello_emited += 1;
-  assert.equal('a', a);
-  assert.equal('b', b);
-}
-e.on('hello', hello);
+  var hello = common.mustCall(function(a, b) {
+    assert.strictEqual('a', a);
+    assert.strictEqual('b', b);
+  });
+
+  ee.once('newListener', function(name, listener) {
+    assert.strictEqual(name, 'hello');
+    assert.strictEqual(listener, hello);
 
-var foo = function() {};
-e.once('foo', foo);
+    var listeners = this.listeners('hello');
+    assert.ok(Array.isArray(listeners));
+    assert.strictEqual(listeners.length, 0);
+  });
 
-console.log('start');
+  ee.on('hello', hello);
+  ee.once('foo', assert.fail);
 
-e.emit('hello', 'a', 'b');
+  assert.ok(Array.isArray(events_new_listener_emitted));
+  assert.strictEqual(events_new_listener_emitted.length, 2);
+  assert.strictEqual(events_new_listener_emitted[0], 'hello');
+  assert.strictEqual(events_new_listener_emitted[1], 'foo');
 
+  assert.ok(Array.isArray(listeners_new_listener_emitted));
+  assert.strictEqual(listeners_new_listener_emitted.length, 2);
+  assert.strictEqual(listeners_new_listener_emitted[0], hello);
+  assert.strictEqual(listeners_new_listener_emitted[1], assert.fail);
+
+  ee.emit('hello', 'a', 'b');
+}
 
 // just make sure that this doesn't throw:
-var f = new events.EventEmitter();
-f.setMaxListeners(0);
+{
+  var f = new EventEmitter();
+
+  f.setMaxListeners(0);
+}
+
+{
+  var listen1 = function() {};
+  var listen2 = function() {};
+  var ee = new EventEmitter();
+
+  ee.once('newListener', function() {
+    var listeners = ee.listeners('hello');
+    assert.ok(Array.isArray(listeners));
+    assert.strictEqual(listeners.length, 0);
+    ee.once('newListener', function() {
+      var listeners = ee.listeners('hello');
+      assert.ok(Array.isArray(listeners));
+      assert.strictEqual(listeners.length, 0);
+    });
+    ee.on('hello', listen2);
+  });
+  ee.on('hello', listen1);
+  // The order of listeners on an event is not always the order in which the
+  // listeners were added.
+  var listeners = ee.listeners('hello');
+  assert.ok(Array.isArray(listeners));
+  assert.strictEqual(listeners.length, 2);
+  assert.strictEqual(listeners[0], listen2);
+  assert.strictEqual(listeners[1], listen1);
+}
 
-assert.deepEqual(['hello', 'foo'], events_new_listener_emited);
-assert.deepEqual([hello, foo], listeners_new_listener_emited);
-assert.equal(1, times_hello_emited);
+// Verify that the listener must be a function
+assert.throws(function() {
+  var ee = new EventEmitter();
 
+  ee.on('foo', null);
+}, /^TypeError: "listener" argument must be a function$/);

tests/check-listener-leaks.js

@@ -19,68 +19,75 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+var common = require('./common');
 var assert = require('assert');
 var events = require('../');
 
-var e = new events.EventEmitter();
-
 // default
-for (var i = 0; i < 10; i++) {
-  e.on('default', function() {});
-}
-assert.ok(!e._events['default'].hasOwnProperty('warned'));
-e.on('default', function() {});
-assert.ok(e._events['default'].warned);
+{
+  var e = new events.EventEmitter();
 
-// specific
-e.setMaxListeners(5);
-for (var i = 0; i < 5; i++) {
-  e.on('specific', function() {});
-}
-assert.ok(!e._events['specific'].hasOwnProperty('warned'));
-e.on('specific', function() {});
-assert.ok(e._events['specific'].warned);
+  for (var i = 0; i < 10; i++) {
+    e.on('default', common.mustNotCall());
+  }
+  assert.ok(!e._events['default'].hasOwnProperty('warned'));
+  e.on('default', common.mustNotCall());
+  assert.ok(e._events['default'].warned);
+
+  // specific
+  e.setMaxListeners(5);
+  for (var i = 0; i < 5; i++) {
+    e.on('specific', common.mustNotCall());
+  }
+  assert.ok(!e._events['specific'].hasOwnProperty('warned'));
+  e.on('specific', common.mustNotCall());
+  assert.ok(e._events['specific'].warned);
 
-// only one
-e.setMaxListeners(1);
-e.on('only one', function() {});
-assert.ok(!e._events['only one'].hasOwnProperty('warned'));
-e.on('only one', function() {});
-assert.ok(e._events['only one'].hasOwnProperty('warned'));
+  // only one
+  e.setMaxListeners(1);
+  e.on('only one', common.mustNotCall());
+  assert.ok(!e._events['only one'].hasOwnProperty('warned'));
+  e.on('only one', common.mustNotCall());
+  assert.ok(e._events['only one'].hasOwnProperty('warned'));
 
-// unlimited
-e.setMaxListeners(0);
-for (var i = 0; i < 1000; i++) {
-  e.on('unlimited', function() {});
+  // unlimited
+  e.setMaxListeners(0);
+  for (var i = 0; i < 1000; i++) {
+    e.on('unlimited', common.mustNotCall());
+  }
+  assert.ok(!e._events['unlimited'].hasOwnProperty('warned'));
 }
-assert.ok(!e._events['unlimited'].hasOwnProperty('warned'));
 
 // process-wide
-events.EventEmitter.defaultMaxListeners = 42;
-e = new events.EventEmitter();
+{
+  events.EventEmitter.defaultMaxListeners = 42;
+  var e = new events.EventEmitter();
 
-for (var i = 0; i < 42; ++i) {
-  e.on('fortytwo', function() {});
-}
-assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
-e.on('fortytwo', function() {});
-assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
-delete e._events['fortytwo'].warned;
+  for (var i = 0; i < 42; ++i) {
+    e.on('fortytwo', common.mustNotCall());
+  }
+  assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
+  e.on('fortytwo', common.mustNotCall());
+  assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
+  delete e._events['fortytwo'].warned;
 
-events.EventEmitter.defaultMaxListeners = 44;
-e.on('fortytwo', function() {});
-assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
-e.on('fortytwo', function() {});
-assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
+  events.EventEmitter.defaultMaxListeners = 44;
+  e.on('fortytwo', common.mustNotCall());
+  assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
+  e.on('fortytwo', common.mustNotCall());
+  assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
+}
 
 // but _maxListeners still has precedence over defaultMaxListeners
-events.EventEmitter.defaultMaxListeners = 42;
-e = new events.EventEmitter();
-e.setMaxListeners(1);
-e.on('uno', function() {});
-assert.ok(!e._events['uno'].hasOwnProperty('warned'));
-e.on('uno', function() {});
-assert.ok(e._events['uno'].hasOwnProperty('warned'));
+{
+  events.EventEmitter.defaultMaxListeners = 42;
+  var e = new events.EventEmitter();
+  e.setMaxListeners(1);
+  e.on('uno', common.mustNotCall());
+  assert.ok(!e._events['uno'].hasOwnProperty('warned'));
+  e.on('uno', common.mustNotCall());
+  assert.ok(e._events['uno'].hasOwnProperty('warned'));
 
-// chainable
-assert.strictEqual(e, e.setMaxListeners(1));
+  // chainable
+  assert.strictEqual(e, e.setMaxListeners(1));
+}

tests/common.js

@@ -1,42 +1,92 @@
+// 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.
+
 var assert = require('assert');
 
+var noop = function() {};
+
 var mustCallChecks = [];
 
-function runCallChecks() {
-  var failed_count = 0;
-  for (var i=0 ; i< mustCallChecks.length; ++i) {
-    var context = mustCallChecks[i];
-    if (context.actual === context.expected) {
-      continue;
+function runCallChecks(exitCode) {
+  if (exitCode !== 0) return;
+
+  var failed = mustCallChecks.filter(function(context) {
+    if ('minimum' in context) {
+      context.messageSegment = 'at least ' + context.minimum;
+      return context.actual < context.minimum;
+    } else {
+      context.messageSegment = 'exactly ' + context.exact;
+      return context.actual !== context.exact;
     }
+  });
 
-    failed_count++;
-    console.log('Mismatched %s function calls. Expected %d, actual %d.',
-                context.name,
-                context.expected,
-                context.actual);
+  failed.forEach(function(context) {
+    console.log('Mismatched %s function calls. Expected %s, actual %d.',
+        context.name,
+        context.messageSegment,
+        context.actual);
     console.log(context.stack.split('\n').slice(2).join('\n'));
-  }
+  });
 
-  assert(failed_count === 0);
+  assert.strictEqual(failed.length, 0);
 }
 
-after(runCallChecks);
+exports.mustCall = function(fn, exact) {
+  return _mustCallInner(fn, exact, 'exact');
+};
+
+function _mustCallInner(fn, criteria, field) {
+  if (typeof criteria == 'undefined') criteria = 1;
 
-exports.mustCall = function(fn, expected) {
-  if (typeof expected !== 'number') expected = 1;
+  if (typeof fn === 'number') {
+    criteria = fn;
+    fn = noop;
+  } else if (fn === undefined) {
+    fn = noop;
+  }
+
+  if (typeof criteria !== 'number')
+    throw new TypeError('Invalid ' + field + ' value: ' + criteria);
 
   var context = {
-    expected: expected,
     actual: 0,
-    stack: (new Error).stack,
+    stack: (new Error()).stack,
     name: fn.name || '<anonymous>'
   };
 
+  context[field] = criteria;
+
+  // add the exit listener only once to avoid listener leak warnings
+  if (mustCallChecks.length === 0) after(function() { runCallChecks(0); });
+
   mustCallChecks.push(context);
 
   return function() {
     context.actual++;
     return fn.apply(this, arguments);
   };
+}
+
+exports.mustNotCall = function(msg) {
+  return function mustNotCall() {
+    assert.fail(msg || 'function should not have been called');
+  };
 };

tests/index.js

@@ -8,7 +8,7 @@ var require = function(file) {
     test(file, function() {
         orig_require(file);
     });
-}
+};
 
 require('./add-listeners.js');
 require('./check-listener-leaks.js');

tests/listener-count.js

@@ -19,6 +19,7 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+require('./common');
 var assert = require('assert');
 var EventEmitter = require('../');