await is only valid in async function

Question

I wrote this code in lib/helper.js

var myfunction = async function(x,y) {
   ....
   return [variableA, variableB]
}
exports.myfunction = myfunct         


        

Answer 1

To use await, its executing context needs to be async in nature

As it said, you need to define the nature of your executing context where you are willing to await a task before anything.

Just put async before the fn declaration in which your async task will execute.

var start = async function(a, b) { 
  // Your async task will execute with await
  await foo()
  console.log('I will execute after foo get either resolved/rejected')
}

Explanation:

In your question, you are importing a method which is asynchronous in nature and will execute in parallel. But where you are trying to execute that async method is inside a different execution context which you need to define async to use await.

 var helper = require('./helper.js');   
 var start = async function(a,b){
     ....
     const result = await helper.myfunction('test','test');
 }
 exports.start = start;

Wondering what's going under the hood

await consumes promise/future / task-returning methods/functions and async marks a method/function as capable of using await.

Also if you are familiar with promises, await is actually doing the same process of promise/resolve. Creating a chain of promise and executes you next task in resolve callback.

For more info you can refer to MDN DOCS.