CODEWITHSUNDEEP
node.jseventsevent-handlingdom-events
Shi Zhang
Shi Zhang

Reputation: 163

Event listener and event emitter separate files

I have three files:

my_emitter.js: instance of EventEmitter object to be shared (let's reference this as "myEmitter")

listener.js: where myEmitter.on() is called

registration_handler.js: where myEmitter.emit() is called

Listener is not receiving emitted event.

With the following code, I run node listener.js first and then node registration_handler.js second.

my_emitter.js:

const EventEmitter = require('events');
const myEmitter = new EventEmitter();
exports.emitter = myEmitter;

listener.js:

const emitterFile = require('./my_emitter');
const myEmitter = emitterFile.emitter;

myEmitter.on('test', (res) => {
    console.log('worked!');
});

//within 5s, let's run registration_handler.js to emit the event
setTimeout(console.log, 5000, 'Done');

registration_handler.js:

const emitterFile = require('./my_emitter');
const myEmitter = emitterFile.emitter;

myEmitter.emit('test');

Console (from listener.js):

Expected:

$ node listener.js
worked!
Done

Actual:

$ node listener.js
Done

Upvotes: 2

Views: 2644

Answers (1)

Waldo Ibarra
Waldo Ibarra

Reputation: 81

For it to work, you have to run them in the same Node.js process, for that, you can create a new file and require both your listener and emitter from there.

// another-file.js

require('./listener');
require('./registration_handler.js');

Running this new file should give you the expected results:

$ node another-file.js
worked!
Done

Upvotes: 4

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