I am trying to do something like this on global scope in nodejs REPL. As per my understanding both the following statements are valid. see docs
let x = await Promise.resolve(2);
let y = await 2;
However, both these statements are throwing an error.
Can somebody explain why?
my node version is v8.9.4
When using Node, the file currently must have an .mjs extension to work.
Top level awaits can be used in browser modules. When used the script tag must include the type attribute which must be set to module:
<script src="/script.js" type="module"></script>
const start = Date.now()
console.log('Pre call.')
await delayedCall()
console.log('Duration:', Date.now() - start)
function delayedCall() {
return new Promise(resolve => setTimeout(() => resolve(), 2000))
}
node ./index.mjs in the terminal.await can only be used within a function that is labeled async, so there are two ways you can approach this.
Note:
There is a proposal in place that may eventually allow the usage of Top level await calls.
The first way is to create a self invoked function like this:
(async function() {
let x = await Promise.resolve(2)
let y = await 2
console.log(x, y)
})()Or the second way is to use .then()
Promise.resolve(2).then(async data => {
let x = data
let y = await 2
console.log(x, y)
})
