dispatcher.js•1.44 kB
'use strict'
const EventEmitter = require('node:events')
class Dispatcher extends EventEmitter {
dispatch () {
throw new Error('not implemented')
}
close () {
throw new Error('not implemented')
}
destroy () {
throw new Error('not implemented')
}
compose (...args) {
// So we handle [interceptor1, interceptor2] or interceptor1, interceptor2, ...
const interceptors = Array.isArray(args[0]) ? args[0] : args
let dispatch = this.dispatch.bind(this)
for (const interceptor of interceptors) {
if (interceptor == null) {
continue
}
if (typeof interceptor !== 'function') {
throw new TypeError(`invalid interceptor, expected function received ${typeof interceptor}`)
}
dispatch = interceptor(dispatch)
if (dispatch == null || typeof dispatch !== 'function' || dispatch.length !== 2) {
throw new TypeError('invalid interceptor')
}
}
return new ComposedDispatcher(this, dispatch)
}
}
class ComposedDispatcher extends Dispatcher {
#dispatcher = null
#dispatch = null
constructor (dispatcher, dispatch) {
super()
this.#dispatcher = dispatcher
this.#dispatch = dispatch
}
dispatch (...args) {
this.#dispatch(...args)
}
close (...args) {
return this.#dispatcher.close(...args)
}
destroy (...args) {
return this.#dispatcher.destroy(...args)
}
}
module.exports = Dispatcher