queue-tea/dist/index.mjs

A simple, robust, persistable job & task queue written in typescript. Full type safety included.

// src/TaskQueue.ts
import { createNanoEvents } from "nanoevents";

// src/Queue.ts
var Queue = class {
  constructor(elements) {
    this.tasks = [];
    this.enqueue = (e) => {
      this.tasks = [...this.tasks, e];
    };
    this.dequeue = () => {
      const task = this.peek();
      this.tasks = this.tasks.slice(1);
      return task;
    };
    this.isEmpty = () => {
      return this.tasks.length === 0;
    };
    this.peek = () => {
      return !this.isEmpty() ? this.tasks[0] : void 0;
    };
    this.length = () => {
      return this.tasks.length;
    };
    this.tasks = elements;
  }
};

// src/utils/sleep.ts
var sleep = (delay) => new Promise((res) => setTimeout(res, delay));

// src/utils/uuid.ts
var uuid = () => "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, (c) => {
  const r = Math.random() * 16 | 0;
  return (c === "x" ? r : r & 3 | 8).toString(16);
});

// src/TaskQueue.ts
var defaultCalculateBackoff = (retryCount) => {
  const noise = Math.random() * 100;
  return Math.min(retryCount * 1e3, 5e3) + noise;
};
var TaskQueue = ({
  initialState = [],
  tasks,
  onChange,
  retryDelay = defaultCalculateBackoff
}) => {
  const events = createNanoEvents();
  const queuedTasks = new Queue(initialState);
  let state = "paused";
  const queueTask = (name, ...options) => {
    const id = uuid();
    queuedTasks.enqueue({
      id,
      name,
      retries: 0,
      options: options[0],
      createdAt: Date.now()
    });
    if (state === "idle") {
      run();
    }
    const task = new Promise((res, rej) => {
      events.on("success", (task2) => {
        if (task2.id === id) {
          res();
        }
        events.on("fail", (task3, error) => {
          if (task3.id === id) {
            rej(error);
          }
        });
      });
    });
    return { id, task };
  };
  const pause = () => {
    state = "paused";
  };
  const isPaused = () => state === "paused";
  const run = async () => {
    state = "running";
    while (!queuedTasks.isEmpty()) {
      if (isPaused()) {
        break;
      }
      const task = queuedTasks.peek();
      if (!task) {
        break;
      }
      try {
        await tasks[task.name](task.options, {
          createdAt: task.createdAt,
          retries: task.retries
        });
        queuedTasks.dequeue();
        onChange == null ? void 0 : onChange(queuedTasks.tasks);
        events.emit("success", task);
      } catch (e) {
        events.emit("fail", task, e);
        await sleep(retryDelay(++task.retries));
      } finally {
        events.emit("change", {
          tasks: [...queuedTasks.tasks],
          remainingTasks: queuedTasks.length()
        });
      }
    }
    state = "idle";
  };
  return {
    run,
    getState: () => state,
    pause,
    getQueueItems: () => [...queuedTasks.tasks],
    addEventListener: (event, callback) => events.on(event, callback),
    queueTask
  };
};

// src/index.ts
var src_default = TaskQueue;
export {
  src_default as default
};