Signal mechanism and event mechanism in Node.js?

  node.js, question

It is found that the signaling mechanism used for interprocess communication in Node.js is very similar to the event mechanism (see the code example below). Is there any reason behind this? Or a design pattern?

signal

child.kill('SIGUSR1');
 process.on('SIGUSR1', function () {
 console.log('Got a SIGUSR1 signal.');
 })

event

eventEmitter.emit('event')
 eventEmitter.on('event', function () {
 console.log('Trigger an event.');
 })

It is essentially a message mechanism, which is a common programming method.