Cannot create async methods on Node on Cloud9

Question

I am porting some code I wrote in the browser, and discovered I can't seem to create asynchronous methods in NodeJS

class Test{
    async hello(){
        return "hello";
    }
}

(async function(){
    let test = new Test();
    let hello = await test.hello();
    console.log(hello);
})();

When I execute this, I get an error:

/home/ubuntu/workspace/test.js:2
    async hello(){
          ^^^^^

SyntaxError: Unexpected identifier
    at createScript (vm.js:56:10)
    at Object.runInThisContext (vm.js:97:10)
    at Module._compile (module.js:542:28)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Timeout.Module.runMain [as _onTimeout] (module.js:604:10)
    at ontimeout (timers.js:386:14)
    at tryOnTimeout (timers.js:250:5)

Is this just not possible in node, or am I don't something incorrect here?

I am running Node 8.x

Your error is on `async test(){` but your code doesn't include that anywhere? — Paul, May 15 '18 at 21:41
@AminMohamedAjani he doesn't need babel to transpile, node supports `async/await` since v7.6 — Marcos Casagrande, May 15 '18 at 21:46
@Paulpro you are correct. I editted my code afterward. I have updated with more recently run code. — Jefferey Cave, May 15 '18 at 21:57

Marcos Casagrande · Accepted Answer · 2018-05-15T22:24:56.040

3

The error that happens in that code is the following:

let hello = await test.hello();
                  ^^^^

SyntaxError: Unexpected identifier

Which happens because you are using await keyword outside of an async function.

From the docs:

The await operator is used to wait for a Promise. It can only be used inside an async function.

class Test{
    async hello(){
        return "hello";
    }
}


(async() => {
  // You can only use `await` inside async function
  let test = new Test();
  let hello = await test.hello();
  console.log(hello);
})();

Is this just not possible in node, or am I don't something incorrect here? 
I am running Node 8.x

Node supports async/await since version 7.6, so you can use it freely.

Update:

If you're getting:

async hello(){
      ^^^^^

SyntaxError: Unexpected identifier

It means you're running on an older node version. Try

console.log(process.version);

And will 100% print a version lower than 7.6.

You may have node 8.x on your cli, but not on cloud9, to update node in cloud9 check the following question:

Update node.js version inside Cloud 9 IDE

edited May 15 '18 at 22:24

answered May 15 '18 at 21:49

Marcos Casagrande

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I agree it works in browser, but I'm getting the same error in node. (cut/paste your code) – Jefferey Cave May 15 '18 at 22:00
You're running on an older node version, 100%. check my updated answer, put the console.log and call `node test.js` in the same environment you're calling the other file. – Marcos Casagrande May 15 '18 at 22:01
Indeed, my IDE and my command line are on different versions (CLI: 8.x, IDE:6.x)... warning to all C9 users. – Jefferey Cave May 15 '18 at 22:04
The solution to my underlying issue: https://stackoverflow.com/questions/30631725/update-node-js-version-inside-cloud-9-ide – Jefferey Cave May 15 '18 at 22:09
If you update your question, specifying you're using C9, I can update the answer, so you can accept it for future users. – Marcos Casagrande May 15 '18 at 22:12
oops, thanks for the subtle nudge. I had upvoted, but forget to accept. – Jefferey Cave May 15 '18 at 22:19

Cannot create async methods on Node on Cloud9

1 Answers1