https://github.com/nwtgck/promise-limiter-npm

Simultaneous Promise Execution Limiter, considering resource
https://github.com/nwtgck/promise-limiter-npm

execution javascript number promise restrict semaphore

Last synced: about 1 month ago
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Simultaneous Promise Execution Limiter, considering resource

• Host: GitHub
• URL: https://github.com/nwtgck/promise-limiter-npm
• Owner: nwtgck
• License: mit
• Created: 2019-04-29T02:07:47.000Z (over 5 years ago)
• Default Branch: develop
• Last Pushed: 2023-03-05T21:58:44.000Z (almost 2 years ago)
• Last Synced: 2024-10-26T17:22:59.509Z (3 months ago)
• Topics: execution, javascript, number, promise, restrict, semaphore
• Language: TypeScript
• Homepage:
• Size: 46.9 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# promise-limiter

[![Node CI](https://github.com/nwtgck/promise-limiter-npm/actions/workflows/ci.yml/badge.svg)](https://github.com/nwtgck/promise-limiter-npm/actions/workflows/ci.yml)

Simultaneous Promise Execution Limiter

## Motivation

`PromiseLimiter` takes **less memory resource**. `PromiseLimiter` does not use a queue of `Promise` to restrict the number of executions.

`PromiseLimiter` uses `await` to block rest of promises. So it takes less memory even if the length of the array bellow is large or using infinite [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream). 

## Installation

Install by npm from this GitHub repository

```bash

npm install -S git+https://github.com/nwtgck/promise-limiter-npm#v0.1.0

```

## Usage

Here is an usage.

```js

const promiseLimiter = new PromiseLimiter(3);

for(const millis of [800, 100, 500, 200, 1000, 400]) {

  const {promise} = await promiseLimiter.run(async () => {

    console.log(`Start: ${millis}`);

    // Sleep for millis

    await new Promise(resolve => setTimeout(resolve, millis));

    console.log(`  Finish: ${millis}`);

    return `Result: ${millis}`;

  });

}

```

Console log is the following.

```txt

Start: 800

Start: 100

Start: 500

  Finish: 100

Start: 200

  Finish: 200

Start: 1000

  Finish: 500

Start: 400

  Finish: 800

  Finish: 400

  Finish: 1000

```

You can use `promise` in `const {promise} = ...` to get fulfilled result of `async () => {...}` in `run()`.