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'use strict';
// Exposing private methods as public in order to test
const EventEmitter = require('events').EventEmitter.compose({
listeners: function(type) this._listeners(type),
emit: function() this._emit.apply(this, arguments),
emitOnObject: function() this._emitOnObject.apply(this, arguments),
removeAllListeners: function(type) this._removeAllListeners(type)
});
exports['test:add listeners'] = function(test) {
let e = new EventEmitter();
let events_new_listener_emited = [];
let times_hello_emited = 0;
e.on("newListener", function (event, listener) {
events_new_listener_emited.push(event)
})
e.on("hello", function (a, b) {
times_hello_emited += 1
test.assertEqual("a", a)
test.assertEqual("b", b)
test.assertEqual(this, e, '`this` pseudo-variable is bound to instance');
})
e.emit("hello", "a", "b")
};
exports['test:remove listeners'] = function(test) {
let count = 0;
function listener1 () {
count++;
}
function listener2 () {
count++;
}
function listener3 () {
count++;
}
let e1 = new EventEmitter();
e1.on("hello", listener1);
test.assertEqual(1, e1.listeners('hello').length);
e1.removeListener("hello", listener1);
test.assertEqual(0, e1.listeners('hello').length);
let e2 = new EventEmitter();
e2.on("hello", listener1);
test.assertEqual(1, e2.listeners('hello').length);
e2.removeListener("hello", listener2);
test.assertEqual(1, e2.listeners('hello').length);
test.assertEqual(listener1, e2.listeners('hello')[0]);
let e3 = new EventEmitter();
e3.on("hello", listener1);
test.assertEqual(1, e3.listeners('hello').length);
e3.on("hello", listener2);
test.assertEqual(2, e3.listeners('hello').length);
e3.removeListener("hello", listener1);
test.assertEqual(1, e3.listeners('hello').length);
test.assertEqual(listener2, e3.listeners('hello')[0]);
};
exports['test: modify in emit'] = function(test) {
let callbacks_called = [ ];
let e = new EventEmitter();
function callback1() {
callbacks_called.push("callback1");
e.on("foo", callback2);
e.on("foo", callback3);
e.removeListener("foo", callback1);
}
function callback2() {
callbacks_called.push("callback2");
e.removeListener("foo", callback2);
}
function callback3() {
callbacks_called.push("callback3");
e.removeListener("foo", callback3);
}
e.on("foo", callback1);
test.assertEqual(1, e.listeners("foo").length);
e.emit("foo");
test.assertEqual(2, e.listeners("foo").length);
test.assertEqual(1, callbacks_called.length);
test.assertEqual('callback1', callbacks_called[0]);
e.emit("foo");
test.assertEqual(0, e.listeners("foo").length);
test.assertEqual(3, callbacks_called.length);
test.assertEqual('callback1', callbacks_called[0]);
test.assertEqual('callback2', callbacks_called[1]);
test.assertEqual('callback3', callbacks_called[2]);
e.emit("foo");
test.assertEqual(0, e.listeners("foo").length);
test.assertEqual(3, callbacks_called.length);
test.assertEqual('callback1', callbacks_called[0]);
test.assertEqual('callback2', callbacks_called[1]);
test.assertEqual('callback3', callbacks_called[2]);
e.on("foo", callback1);
e.on("foo", callback2);
test.assertEqual(2, e.listeners("foo").length);
e.removeAllListeners("foo");
test.assertEqual(0, e.listeners("foo").length);
// Verify that removing callbacks while in emit allows emits to propagate to
// all listeners
callbacks_called = [ ];
e.on("foo", callback2);
e.on("foo", callback3);
test.assertEqual(2, e.listeners("foo").length);
e.emit("foo");
test.assertEqual(2, callbacks_called.length);
test.assertEqual('callback2', callbacks_called[0]);
test.assertEqual('callback3', callbacks_called[1]);
test.assertEqual(0, e.listeners("foo").length);
};
exports['test:adding same listener'] = function(test) {
function foo() {}
let e = new EventEmitter();
e.on("foo", foo);
e.on("foo", foo);
test.assertEqual(
1,
e.listeners("foo").length,
"listener reregistration is ignored"
);
}
exports['test:errors are reported if listener throws'] = function(test) {
let e = new EventEmitter(),
reported = false;
e.on('error', function(e) reported = true)
e.on('boom', function() { throw new Error('Boom!') });
e.emit('boom', 3);
test.assert(reported, 'error should be reported through event');
};
exports['test:emitOnObject'] = function(test) {
let e = new EventEmitter();
e.on("foo", function() {
test.assertEqual(this, e, "`this` should be emitter");
});
e.emitOnObject(e, "foo");
e.on("bar", function() {
test.assertEqual(this, obj, "`this` should be other object");
});
let obj = {};
e.emitOnObject(obj, "bar");
};
exports['test:once'] = function(test) {
let e = new EventEmitter();
let called = false;
e.once('foo', function(value) {
test.assert(!called, "listener called only once");
test.assertEqual(value, "bar", "correct argument was passed");
});
e.emit('foo', 'bar');
e.emit('foo', 'baz');
};
exports["test romeving once"] = function(test) {
let e = require("events").EventEmitterTrait.create();
e.once("foo", function() { test.pass("listener was called"); });
e.once("error", function() { test.fail("error event was emitted"); });
e._emit("foo", "bug-656684");
};
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