mailbox.ts

utils/mailbox.ts

No strong subsystem tag

Lines

1596

Bytes

Exports

Imports

Keywords

What this is

This page documents one file from the repository and includes its full source so you can read it without leaving the docs site.

Beginner explanation

This file is one piece of the larger system. Its name, directory, imports, and exports show where it fits. Start by reading the exports and related files first.

How it is used

Start from the exports list and related files. Those are the easiest clues for where this file fits into the system.

Expert explanation

Architecturally, this file intersects with general runtime concerns. It contains 74 lines, 1 detected imports, and 3 detected exports.

Important relationships

Detected exports

MessageSource
Message
Mailbox

Keywords

messagequeuewaiterresolveprivatewaitersrevisionnotifyvoidchanged

Detected imports

./signal.js

Source notes

This page embeds the full file contents. Small or leaf files are still indexed honestly instead of being over-explained.

Open parent directory

Full source

import { createSignal } from './signal.js'

export type MessageSource = 'user' | 'teammate' | 'system' | 'tick' | 'task'

export type Message = {
  id: string
  source: MessageSource
  content: string
  from?: string
  color?: string
  timestamp: string
}

type Waiter = {
  fn: (msg: Message) => boolean
  resolve: (msg: Message) => void
}

export class Mailbox {
  private queue: Message[] = []
  private waiters: Waiter[] = []
  private changed = createSignal()
  private _revision = 0

  get length(): number {
    return this.queue.length
  }

  get revision(): number {
    return this._revision
  }

  send(msg: Message): void {
    this._revision++
    const idx = this.waiters.findIndex(w => w.fn(msg))
    if (idx !== -1) {
      const waiter = this.waiters.splice(idx, 1)[0]
      if (waiter) {
        waiter.resolve(msg)
        this.notify()
        return
      }
    }
    this.queue.push(msg)
    this.notify()
  }

  poll(fn: (msg: Message) => boolean = () => true): Message | undefined {
    const idx = this.queue.findIndex(fn)
    if (idx === -1) return undefined
    return this.queue.splice(idx, 1)[0]
  }

  receive(fn: (msg: Message) => boolean = () => true): Promise<Message> {
    const idx = this.queue.findIndex(fn)
    if (idx !== -1) {
      const msg = this.queue.splice(idx, 1)[0]
      if (msg) {
        this.notify()
        return Promise.resolve(msg)
      }
    }
    return new Promise<Message>(resolve => {
      this.waiters.push({ fn, resolve })
    })
  }

  subscribe = this.changed.subscribe

  private notify(): void {
    this.changed.emit()
  }
}