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Promise mutex/lock implemented with the Explicit Resource Management proposal
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| export const createLock = () => { | |
| let promise = Promise.resolve(); | |
| return { | |
| async acquire(): Promise<Disposable> { | |
| const { promise: next, resolve } = Promise.withResolvers<void>(); | |
| const prev = promise; | |
| promise = next; | |
| await prev; | |
| return { [Symbol.dispose]: resolve }; | |
| }, | |
| }; | |
| }; | |
| const lock = createLock(); | |
| (async () => { | |
| console.log(`a: acquiring`); | |
| using _lck = await lock.acquire(); | |
| console.log(`a: acquired`); | |
| await new Promise((res) => setTimeout(res, 50)); | |
| console.log(`a: releasing`); | |
| })(); | |
| (async () => { | |
| console.log(`b: acquiring`); | |
| using _lck = await lock.acquire(); | |
| console.log(`b: acquired`); | |
| await new Promise((res) => setTimeout(res, 50)); | |
| console.log(`b: releasing`); | |
| })(); | |
| (async () => { | |
| await new Promise((res) => setTimeout(res, 50)); | |
| console.log(`c: acquiring`); | |
| using _lck = await lock.acquire(); | |
| console.log(`c: acquired`); | |
| await new Promise((res) => setTimeout(res, 50)); | |
| console.log(`c: releasing`); | |
| })(); |
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