npmpackage.info

@algonomia/semaphore-async-await

🎌 Promise based Semaphore suitable to be used with async/await.

1.0.0

MIT

TypeScript

41.92 kB

4,003 1.7

Installations

npm install @algonomia/semaphore-async-await

Developer Guide

BETA

Typescript

No

Module System

CommonJS

Min. Node Version

>=4.1

Node Version

9.4.0

NPM Version

6.4.1 Score

71.9

Supply Chain

99.3

Quality

74.8

Maintenance

100

Vulnerability

100

License

Pull Requests

Open

0

Total

0

Closed

0

Issues

Open

0

Total

0

Closed

0

Releases

Unable to fetch releases

Contributors

Unable to fetch Contributors

View all 1 contributors

Languages

TypeScript

TypeScript (100%)

Developer

Algonomia

Download Statistics

Total Downloads

4,003

Last Day

Last Week

Last Month

Last Year

1,183

GitHub Statistics

74 Commits

1 Watching

1 Branches

1 Contributors

Maintainers

Package Meta Information

Latest Version

1.0.0

Package Id

@algonomia/semaphore-async-await@1.0.0

Unpacked Size

41.92 kB

Size

10.56 kB

File Count

NPM Version

6.4.1

Node Version

9.4.0

Total Downloads

Cumulative downloads

Total Downloads

4,003

Last day

Compared to previous day

Last week

-62.5%

Compared to previous week

Last month

-38.3%

Compared to previous month

Last year

-15.4%

1,183

Compared to previous year

Daily Downloads

Weekly Downloads

Monthly Downloads

Yearly Downloads

Dev Dependencies

@types/jest husky jest ts-jest tslint typedoc typescript

Versions

JavaScript Semaphore

A promise-based semaphore implementation suitable to be used with async/await. (This fork includes a function to wait for all queued promises to finish.)

Spare me the details, all I need is a lock.

Just import { Lock } from 'semaphore-async-await', acquire the lock by calling await lock.acquire() and release it when you're done by calling lock.release().

But JavaScript is single-threaded and doesn't need semaphores!

This package can be used to synchronize functions that span multiple iterations of the event loop and prevent other code from being executed while your function is waiting.

Suppose you have a function

1async function criticalFunction() {
2  const data = await getDataFromDb();
3  const modifiedData = await asynchronouslyDoStuffWithData(data);
4  return writeDataBackToDb(modifiedData);
5}

Calling this function repeatedly could lead to overlapping read/writes. To avoid this problem, a lock can be added like so:

1const lock = new Semaphore(1);
2
3async function criticalFunctionSynchronous() {
4  await lock.acquire();
5
6  try {
7    await criticalFunction();
8  } finally {
9    lock.release();
10  }
11}

Asynchronous functions like criticalFunction are executed in multiple chunks of code on the event loop, this package makes it possible to enforce an ordering in these chunks.

Install

yarn add semaphore-async-await

API

Usage

1import Semaphore from 'semaphore-async-await';
2
3(async () => {
4
5  // A Semaphore with one permit is a lock
6  const lock = new Semaphore(1);
7
8  // Helper function used to wait for the given number of milliseconds
9  const wait = (ms) => new Promise(r => setTimeout(r, ms));
10
11  let globalVar = 0;
12
13  (async () => {
14    // This waits (without blocking the event loop) until a permit becomes available
15    await lock.wait();
16    const localCopy = globalVar;
17    await wait(500);
18    globalVar = localCopy + 1;
19    // Signal releases the lock and lets other things run
20    lock.signal();
21  })();
22
23  // This returns false because the function above has acquired the lock
24  // and is scheduled to continue executing once the main function yields or
25  // returns
26  console.log(lock.tryAcquire() === false);
27
28  // Similar to the function above but using waitFor instead of wait. We
29  // give it five seconds to wait which is enough time for it to acquire
30  // the lock
31  (async () => {
32    // This waits for at least five seconds, trying to acquire a permit.
33    const didAcquireLock = await lock.waitFor(5000);
34    if (didAcquireLock) {
35      const localCopy = globalVar;
36      await wait(500);
37      globalVar = localCopy + 1;
38      // Signal releases the lock and lets other things run
39      lock.signal();
40    }
41  })();
42
43  // Alternative to using wait()/signal() directly
44  lock.execute(async () => {
45    const localCopy = globalVar;
46    await wait(500);
47    globalVar = localCopy + 1;
48  });
49
50  // Wait for everything to finish
51  await lock.finishAll();
52
53  console.log(globalVar === 3);
54})();

License

MIT

No vulnerabilities found.

10

Binary-Artifacts

Determines if the project has generated executable (binary) artifacts in the source repository.

10

License

Determines if the project has defined a license.

0

Code-Review

Determines if the project requires human code review before pull requests (aka merge requests) are merged.

0

Maintained

Determines if the project is "actively maintained".

0

SAST

Determines if the project uses static code analysis.

0

CII-Best-Practices

Determines if the project has an OpenSSF (formerly CII) Best Practices Badge.

0

Security-Policy

Determines if the project has published a security policy.

0

Fuzzing

Determines if the project uses fuzzing.

0

Branch-Protection

Determines if the default and release branches are protected with GitHub's branch protection settings.

0

Vulnerabilities

Determines if the project has open, known unfixed vulnerabilities.

Reason

69 existing vulnerabilities detected

Details

Warn: Project is vulnerable to: GHSA-v88g-cgmw-v5xw
Warn: Project is vulnerable to: GHSA-fwr7-v2mv-hh25
Warn: Project is vulnerable to: GHSA-67hx-6x53-jw92
Warn: Project is vulnerable to: GHSA-832h-xg76-4gv6
Warn: Project is vulnerable to: GHSA-cwfw-4gq5-mrqx
Warn: Project is vulnerable to: GHSA-g95f-p29q-9xw4
Warn: Project is vulnerable to: GHSA-grv7-fg5c-xmjg
Warn: Project is vulnerable to: GHSA-9vvw-cc9w-f27h
Warn: Project is vulnerable to: GHSA-gxpj-cx7g-858c
Warn: Project is vulnerable to: GHSA-hr2v-3952-633q
Warn: Project is vulnerable to: GHSA-h6ch-v84p-w6p9
Warn: Project is vulnerable to: GHSA-ff7x-qrg7-qggm
Warn: Project is vulnerable to: GHSA-qrmc-fj45-qfc2
Warn: Project is vulnerable to: GHSA-pfrx-2q88-qq97
Warn: Project is vulnerable to: GHSA-q42p-pg8m-cqh6
Warn: Project is vulnerable to: GHSA-w457-6q6x-cgp9
Warn: Project is vulnerable to: GHSA-62gr-4qp9-h98f
Warn: Project is vulnerable to: GHSA-f52g-6jhx-586p
Warn: Project is vulnerable to: GHSA-2cf5-4w76-r9qv
Warn: Project is vulnerable to: GHSA-3cqr-58rm-57f8
Warn: Project is vulnerable to: GHSA-g9r4-xpmj-mj65
Warn: Project is vulnerable to: GHSA-q2c6-c6pm-g3gh
Warn: Project is vulnerable to: GHSA-765h-qjxv-5f44
Warn: Project is vulnerable to: GHSA-f2jv-r9rf-7988
Warn: Project is vulnerable to: GHSA-44pw-h2cw-w3vq
Warn: Project is vulnerable to: GHSA-vfrc-7r7c-w9mx
Warn: Project is vulnerable to: GHSA-7wwv-vh3v-89cq
Warn: Project is vulnerable to: GHSA-jp4x-w63m-7wgm
Warn: Project is vulnerable to: GHSA-c429-5p7v-vgjp
Warn: Project is vulnerable to: GHSA-43f8-2h32-f4cj
Warn: Project is vulnerable to: GHSA-qqgx-2p2h-9c37
Warn: Project is vulnerable to: GHSA-2pr6-76vf-7546
Warn: Project is vulnerable to: GHSA-8j8c-7jfh-h6hx
Warn: Project is vulnerable to: GHSA-896r-f27r-55mw
Warn: Project is vulnerable to: GHSA-9c47-m6qq-7p4h
Warn: Project is vulnerable to: GHSA-fvqr-27wr-82fm
Warn: Project is vulnerable to: GHSA-4xc9-xhrj-v574
Warn: Project is vulnerable to: GHSA-x5rq-j2xg-h7qm
Warn: Project is vulnerable to: GHSA-jf85-cpcp-j695
Warn: Project is vulnerable to: GHSA-p6mc-m468-83gw
Warn: Project is vulnerable to: GHSA-29mw-wpgm-hmr9
Warn: Project is vulnerable to: GHSA-35jh-r3h4-6jhm
Warn: Project is vulnerable to: GHSA-7px7-7xjx-hxm8
Warn: Project is vulnerable to: GHSA-x5pg-88wf-qq4p
Warn: Project is vulnerable to: GHSA-5v2h-r2cx-5xgj
Warn: Project is vulnerable to: GHSA-rrrm-qjm4-v8hf
Warn: Project is vulnerable to: GHSA-f9cm-qmx5-m98h
Warn: Project is vulnerable to: GHSA-7wpw-2hjm-89gp
Warn: Project is vulnerable to: GHSA-952p-6rrq-rcjv
Warn: Project is vulnerable to: GHSA-f8q6-p94x-37v3
Warn: Project is vulnerable to: GHSA-vh95-rmgr-6w4m / GHSA-xvch-5gv4-984h
Warn: Project is vulnerable to: GHSA-w9mr-4mfr-499f
Warn: Project is vulnerable to: GHSA-5fw9-fq32-wv5p
Warn: Project is vulnerable to: GHSA-6394-6h9h-cfjg
Warn: Project is vulnerable to: GHSA-hj48-42vr-x3v9
Warn: Project is vulnerable to: GHSA-hrpp-h998-j3pp
Warn: Project is vulnerable to: GHSA-6g33-f262-xjp4
Warn: Project is vulnerable to: GHSA-p8p7-x288-28g6
Warn: Project is vulnerable to: GHSA-c2qf-rxjj-qqgw
Warn: Project is vulnerable to: GHSA-4rq4-32rv-6wp6
Warn: Project is vulnerable to: GHSA-64g7-mvw6-v9qj
Warn: Project is vulnerable to: GHSA-2m39-62fm-q8r3
Warn: Project is vulnerable to: GHSA-mf6x-7mm4-x2g7
Warn: Project is vulnerable to: GHSA-jgrx-mgxx-jf9v
Warn: Project is vulnerable to: GHSA-g7q5-pjjr-gqvp
Warn: Project is vulnerable to: GHSA-72xf-g2v4-qvf3
Warn: Project is vulnerable to: GHSA-7p7h-4mm5-852v
Warn: Project is vulnerable to: GHSA-c4w7-xm78-47vh
Warn: Project is vulnerable to: GHSA-p9pc-299p-vxgp

Score

1.7

/10

Last Scanned on 2024-12-30

The Open Source Security Foundation is a cross-industry collaboration to improve the security of open source software (OSS). The Scorecard provides security health metrics for open source projects.

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