Synchronize
- npm;
npm install @jaenster/synchronized - yarn;
yarn add @jaenster/synchronized - deno;
import {Synchronized} from 'https://github.com/jaenster/synchronized/raw/master/src/index.ts'
Problem
Ever had an async method that should not run twice at the same time?
Solution
synchronize with a decorator!
Example
import {Synchronized} from "@jaenster/synchronized";
// generate a promise which delays
const delay = ms => new Promise<void>(resolve => setTimeout(resolve, ms));
class Worker {
@Synchronized()
async runTask(id: number) {
// Do something
// simulate some work
console.log(`task #${id} started`);
await delay(500);
console.log(`task #${id} done`);
}
}
(async () => {
const worker = new Worker();
await Promise.all([
worker.runTask(0),
worker.runTask(1),
worker.runTask(2),
worker.runTask(3),
]);
})();What happens
If Worker.runTask has the decorator Synchronized,it takes 2 seconds to run and logs:
- task #0 started
- task #0 done
- task #1 started
- task #1 done
- task #2 started
- task #2 done
- task #3 started
- task #3 done
if Synchronized is omitted from the example code, it takes a half second to run and logs:
- task #0 started
- task #1 started
- task #2 started
- task #3 started
- task #0 done
- task #1 done
- task #2 done
- task #3 done