Promistop

A lightweight utility to create cancellable promises in JavaScript

Promistop adds .cancel() and .isCancelled() methods to any async task, with optional AbortController support.

🔧 Features

• Cancel any async function using .cancel(reason?)
• Check if a promise was cancelled using .isCancelled()
• Optional support for AbortSignal (e.g., for fetch)
• Tiny and framework-agnostic

📦 Installation

npm install promistop

🚀 Usage

- API Call with fetch and AbortSignal

import { makeCancellable } from "promistop";

const cancellable = makeCancellable(
  async ({ signal }) => {
    const res = await fetch("/api/data", { signal });
    return res.json();
  },
  { abortable: true }
);

cancellable
  .then((data) => console.log(data))
  .catch((err) => console.error(err));

// Cancel the request if needed
cancellable.cancel("User navigated away");

- Wrapping a setTimeout

import { makeCancellable } from "promistop";

const delay = (ms: number) =>
  makeCancellable(
    () =>
      new Promise((resolve) => {
        const id = setTimeout(() => resolve("Done waiting"), ms);
        // Optional cleanup if extending
        return () => clearTimeout(id);
      }),
    { cancelReason: "Timeout manually cancelled" }
  );

const timeoutPromise = delay(3000);

timeoutPromise.then(console.log).catch(console.error);

// Cancel before it completes
setTimeout(() => {
  timeoutPromise.cancel("Cancelled early");
}, 1000);

🧩 API

makeCancellable(asyncFn, options?)

Creates a cancellable promise from any async function.

Parameters:

• asyncFn: (params?: { signal?: AbortSignal }) => Promise<T> | T – your async task
• options:
  • abortable?: boolean – enable AbortController support
  • cancelReason?: string – default cancel message

Returns:

A CancellablePromise<T> with:

• .cancel(reason?) - Cancels the promise with an optional reason
• .isCancelled() - Returns whether the promise has been cancelled

⚠️ Issues/Errors

For any hiccups with the package, drop an email to Kumarashish87998@gmail.com with "Error || Promistop" as the subject. 📧