Promise.timeout NPM

promise.timeout

add timeout support for async function

Install

$ pnpm add promise.timeout

Note

this module targets ES5 environment.
this module require global AbortController, Node.js has builtin global since v15

API

var ptimeout = require('promise.timeout')

ptimeout(fn, timeout)

fn the async function
timeout in ms

var ptimeout = require('promise.timeout')

// a function will cost 20ms
function test() {
  return new Promise(function (resolve, reject) {
    setTimeout(function () {
      resolve(20)
    }, 20)
  })
}

var test10 = ptimeout(test, 10)
var test50 = ptimeout(test, 50)

// 10 timeout
try {
  await test10()
} catch (e) {
  e.should.be.ok()
  e.should.be.instanceof(ptimeout.TimeoutError)
  e.message.should.match(/timeout/)
  e.timeout.should.equal(10)
}

// 50 ok
var _50 = await test50()
_50.should.be.ok()
_50.should.equal(20)

singal

ptimeout will provide an extra runtime argument signal: AbortSignal, you can use the signal to register abort action. when timeout reached, the abort action will be executed

var ptimeout = require('promise.timeout')

// a function will cost 20ms
function test(signal) {
  return new Promise(function (resolve, reject) {
    var timer = setTimeout(function () {
      resolve(20)
    }, 20)

    // clean up
    signal.addEventListener('abort', () => {
      clearTimeout(timer)
    })
  })
}

var test10 = ptimeout(test, 10)
try {
  await test10()
} catch (e) {
  e.should.ok()
}

FAQ

Q: why move to `AbortController`

A:

easy to type, easy to strip signal argument, easy to use with TypeScript
AND it's shiped in Node.js https://nodejs.org/api/globals.html#class-abortcontroller
for browser, users should consider a polyfill for AbortController & AbortSignal if not provided nativly

Q: Why onCancel

A: Think `onCancel` like the AbortController

with AbortController you need to

function normalFn(a, r, g, s, controller: AbortController) {
  controller.signal.addEventListener('abort', () => {
    // cancel operations that starts in `normalFn` body
  })
}

and ptimeout will call the controller.abort() if any timeout exceeds
and with onCancel, you provide a cancel operation to ptimeout, ptimeout will call that

That's the same, and I don't want to depend on an extra package abort-controller