How can I wait In Node.js (JavaScript)? l need to pause for a period of time

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Update Jan 2021: You can even do it in the Node REPL interactive using --experimental-repl-await flag

$ node --experimental-repl-await
> const delay = ms => new Promise(resolve => setTimeout(resolve, ms))
> await delay(1000) /// waiting 1 second.

A new answer to an old question. Today ( Jan 2017 June 2019) it is much easier. You can use the new async/await syntax.
For example:

async function init() {
  console.log(1);
  await sleep(1000);
  console.log(2);
}

function sleep(ms) {
  return new Promise((resolve) => {
    setTimeout(resolve, ms);
  });
}

For using async/await out of the box without installing and plugins, you have to use node-v7 or node-v8, using the --harmony flag.

Update June 2019: By using the latest versions of NodeJS you can use it out of the box. No need to provide command line arguments. Even Google Chrome support it today.

Update May 2020:
Soon you will be able to use the await syntax outside of an async function. In the top level like in this example

await sleep(1000)
function sleep(ms) {
  return new Promise((resolve) => {
    setTimeout(resolve, ms);
  });
}

The proposal is in stage 3.
You can use it today by using webpack 5 (alpha),

More info:

  • Harmony Flag in Nodejs: https://nodejs.org/en/docs/es6/
  • All NodeJS Version for download: https://nodejs.org/en/download/releases/

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