问题
I want to emit events from one file/module/script and listen to them in another file/module/script. How can I share the emitter variable between them without polluting the global namespace?
Thanks!
回答1:
You can pass arguments to require calls thusly:
var myModule = require('myModule')(Events)
And then in "myModule"
module.exports = function(Events) {
// Set up Event listeners here
}
With that said, if you want to share an event emitter, create an emitter object and then pass to your "file/module/script" in a require call.
Update:
Though correct, this is a code smell as you are now tightly coupling the modules together. Instead, consider using a centralized event bus that can be required into each module.
回答2:
@srquinn is correct, you should use a shared single instance:
eventBus.js:
const EventEmitter = require('events');
const emitter = new EventEmitter();
emitter.on('uncaughtException', function (err) {
console.error(err);
});
module.exports = emitter;
Usage:
var bus = require('../path/to/eventBus');
// Register event listener
bus.on('eventName', function () {
console.log('triggered!');
});
// Trigger the event somewhere else
bus.emit('eventName');
回答3:
Why not use the EventEmitter of the global process object?
process.on('customEvent', function(data) {
...
});
process.emit('customEvent', data);
Pro: You can disable or completely remove a module (for instance a tracker), without removing all your tracking code within your routes. I'm doing exactly that for node-trackable.
Con: I don't now, but please let me know if you see a catch here ;-)
来源:https://stackoverflow.com/questions/10659266/how-do-you-share-an-eventemitter-in-node-js