iopa/src/util/events.ts

API-first, Internet of Things (IoT) stack for Typescript, official implementation of the Internet Open Protocols Alliance (IOPA) reference pattern

import { IExtendableEventTarget, ITraceEvent, ITraceEvents } from '@iopa/types'

export class ExtendableEventTarget
  extends EventTarget
  implements IExtendableEventTarget
{
  public constructor() {
    super()
  }
  public dispatchEvent(event: Event): boolean {
    if (!(event instanceof Event)) {
      const { type, ...rest } = event as Record<string, any>
      const eventInstance = new Event(type)
      Object.keys(rest).forEach((key) => {
        eventInstance[key] = rest[key]
      })
      event = eventInstance
    }
    return super.dispatchEvent(event)
  }
  public async dispatchEventExtendable(event: Event): Promise<boolean> {
    const promises: Promise<any>[] = []
    const extendableEvent: ExtendableEvent = {
      ...event,
      waitUntil: (p: Promise<any>) => {
        promises.push(p)
      }
    }
    const result = this.dispatchEvent(extendableEvent)
    await Promise.all(promises)
    return result
  }
}

export class TraceEvent extends Event implements ITraceEvent {
  public label: string

  public get type(): keyof ITraceEvents {
    return super.type as keyof ITraceEvents
  }

  public constructor(
    type: string,
    eventInitDict?: EventInit & { label: string }
  ) {
    const { label, ...options } = eventInitDict || {}
    super(type, options)
    this.label = label
  }
}