Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/mgtitimoli/await-mutex
Promised based Javascript Mutex
https://github.com/mgtitimoli/await-mutex
async-await async-programming javascript mutex mutex-synchronisation nodejs promises
Last synced: 8 days ago
JSON representation
Promised based Javascript Mutex
- Host: GitHub
- URL: https://github.com/mgtitimoli/await-mutex
- Owner: mgtitimoli
- Created: 2015-12-24T21:33:35.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2018-08-29T14:17:41.000Z (about 6 years ago)
- Last Synced: 2024-10-03T07:14:04.402Z (about 1 month ago)
- Topics: async-await, async-programming, javascript, mutex, mutex-synchronisation, nodejs, promises
- Language: JavaScript
- Size: 10.7 KB
- Stars: 41
- Watchers: 6
- Forks: 7
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
Awesome Lists containing this project
README
# await-mutex
Promised based Mutex for cases where you need to synchronize sequentially the access to a single resource from multiple locations.
A typical use case for a mutex is when multiple asynchronous processes are fired and all of them have to execute another, **but the same**, asynchronous process as they arrive, one at a time, waiting for previous call (if any) to finish before calling it again.
## Examples
### file-appender.js
Let you create an object to perform file appends **one at a time**.
```js
import * as fs from "fs";
import Mutex from "await-mutex";
export default class FileAppender {
constructor(filename) {
this._filename = filename;
this._mutex = new Mutex();
}
async append(data, options = undefined) {
let unlock = await this._mutex.lock();
fs.appendFile(this._filename, data, options, error => {
unlock();
if (error) {
throw error;
}
});
}
}
```
## API
```js
import Mutex from "await-mutex";
```
### Mutex
Creates an instance of Mutex (can not be called without **new**).
```js
let mutex = new Mutex();
```
### Mutex.prototype.isLocked
Returns if the mutex instance is (true) or not locked (false).
```js
let unlock = await mutex.lock();
console.log(mutex.isLocked()); // prints true
```
### Mutex.prototype.lock: Promise
- Waits until the mutex is unlocked and then locks it.
- It returns an [ES2015 standard Promise](https://tc39.github.io/ecma262/#sec-promise-objects) (this allows the use of [async/await](http://tc39.github.io/ecmascript-asyncawait/)) which gets resolved once the mutex is unlocked.
- The promise resolution value is an **unlock function** that has to be called once the mutex needs to be unlocked.
```js
async function someFunc(mutex) {
let unlock = await mutex.lock(); // wait until mutex is unlocked
setTimeout(unlock, 3000);
console.log(someFunc.name);
}
async function someOtherFunc(mutex) {
let unlock = await mutex.lock(); // wait until mutex is unlocked
console.log(someOtherFunc.name);
}
let mutex = new Mutex();
someFunc(mutex); // prints SomeFunc inmediately
someOtherFunc(mutex); // waits 3 secs for mutex to be unlocked and then prints SomeOtherFunc
```
## Installation
With [npm](http://npmjs.org) do:
```
npm install --save await-mutex
```
## Contributing
### Contributors
- [Mauro Titimoli](https://github.com/mgtitimoli)
### How to
Take a look to the [Contributing Guide](CONTRIBUTING.md)
## license
[Unlicense](http://unlicense.org/).