Combination of async function await setTimeout

Question

I am trying to use the new async features and I hope solving my problem will help others in the future  This is my code which is working     async function asyncGenerator            other code     while  goOn             other code       var fileList   await listFiles nextPageToken         var parents   await requestParents fileList            other code              other code        function listFiles token        return gapi client drive files list          maxResults   sizeResults         pageToken   token         q   query               The problem is  that my while loop runs too fast and the script sends too many requests per second to the google API  Therefore I would like to build a sleep function which delays the request  Thus I could also use this function to delay other requests  If there is another way to delay the request  please let me know   Anyway  this is my new code which does not work  The response of the request is returned to the anonymous async function within the setTimeout  but I just do not know how I can return the response to the sleep function resp  to the initial asyncGenerator function     async function asyncGenerator            other code     while  goOn             other code       var fileList   await sleep listFiles  nextPageToken         var parents   await requestParents fileList            other code              other code        function listFiles token        return gapi client drive files list          maxResults   sizeResults         pageToken   token         q   query                async function sleep fn  par        return await setTimeout async function           await fn par          3000  fn  par         I have already tried some options  storing the response in a global variable and return it from the sleep function  callback within the anonymous function  etc

User · Answer

The following code works in Chrome and Firefox and maybe other browsers.

function timeout(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}
async function sleep(fn, ...args) {
    await timeout(3000);
    return fn(...args);
}

But in Internet Explorer I get a Syntax Error for the "(resolve **=>** setTimeout..."

User · Answer

Made a util inspired from Dave s answer  Basically passed in a done callback to call when the operation is finished      Function to timeout if a request is taking too long const setAsyncTimeout    cb  timeout   0    gt  new Promise  resolve  reject    gt      cb resolve     setTimeout      gt  reject  Request is taking too long to response    timeout         This is how I use it   try     await setAsyncTimeout async done   gt        const requestOne   await someService post configs       const requestTwo   await someService get configs       const requestThree   await someService post configs       done         5000      5 seconds max for this set of operations   catch  err      console error   Timeout  Unable to complete the operation    err

User · Answer

var testAwait   function          var promise   new Promise  resolve  reject    gt            setTimeout      gt                resolve  Inside test await               1000               return promise     var asyncFunction   async function         await testAwait   then  data    gt            console log data              return  hello asyncFunction      asyncFunction   then  data    gt        console log data          Inside test await   hello asyncFunction

User · Answer

Update 2020 You can await setTimeout with Node js 15 or above  const timersPromises   require  timers promises      async      gt      const result   await timersPromises setTimeout 2000   resolved        Executed after 2 seconds   console log result       quot resolved quot        Timers Promises API  https   nodejs org api timers html timers timers promises api  library already built in Node   Note  Stability  1 - Use of the feature is not recommended in production environments

User · Answer

If you would like to use the same kind of syntax as setTimeout you can write a helper function like this   const setAsyncTimeout    cb  timeout   0    gt  new Promise resolve   gt        setTimeout      gt            cb            resolve           timeout         You can then call it like so   const doStuffAsync   async      gt        await setAsyncTimeout      gt               Do stuff        1000        await setAsyncTimeout      gt               Do more stuff        500        await setAsyncTimeout      gt               Do even more stuff        2000       doStuffAsync      I made a gist  https   gist github com DaveBitter f44889a2a52ad16b6a5129c39444bb57

User · Answer

Since Node 7 6  you can combine the functions promisify function from the utils module with setTimeout       Node js  const sleep   require  util   promisify setTimeout    Javascript  const sleep   m   gt  new Promise r   gt  setTimeout r  m     Usage   async      gt        console time  Slept for       await sleep 3000      console timeEnd  Slept for

User · Answer

await setTimeout     gt     200    Will work if your Node version is 15 and above

User · Answer

This is my version with nodejs now in 2020 in AWS labdas  const sleep   require  util   promisify setTimeout   async function f1  some          async function f2  thing          module exports someFunction   async event   gt                await f1 some      await sleep 5000      await f2 thing

User · Answer

This is a quicker fix in one-liner   Hope this will help      WAIT FOR 200 MILISECONDS TO GET DATA    await setTimeout     gt     200

User · Answer

setTimeout is not an async function  so you can t use it with ES7 async-await  But you could implement your sleep function using ES6 Promise   function sleep  fn  par      return new Promise  resolve    gt           wait 3s before calling fn par      setTimeout      gt  resolve fn par    3000           Then you ll be able to use this new sleep function with ES7 async-await   var fileList   await sleep listFiles  nextPageToken    Please  note that I m only answering your question about combining ES7 async await with setTimeout  though it may not help solve your problem with sending too many requests per second     Update  Modern node js versions has a buid-in async timeout implementation  accessible via util promisify helper   const  promisify    require  util    const setTimeoutAsync   promisify setTimeout

User · Answer

Your sleep function does not work because setTimeout does not  yet   return a promise that could be awaited  You will need to promisify it manually  function timeout ms        return new Promise resolve   gt  setTimeout resolve  ms      async function sleep fn     args        await timeout 3000       return fn    args      Btw  to slow down your loop you probably don t want to use a sleep function that takes a callback and defers it like this  I recommend  while  goOn         other code   var  parents    await Promise all         listFiles nextPageToken  then requestParents         timeout 5000             other code    which lets the computation of parents take at least 5 seconds

User · Answer

The quick one-liner  inline way   await new Promise resolve   gt  setTimeout resolve  1000

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