See the following code, we have our function and we are calling an async function

            function ShowErrorToUI(Data, Message) {
                console.log(`Data point #1`);
                var BoolData = undefined;
                let myParameterData = false;
                async function asyncMyCall() {
                    try {
                        myParameterData = await ReadPLCVariable('%s%PLC1.MAIN.doorAtHome%/s%');
                        console.log(`myParameterData = ${myParameterData}`);                      
                        BoolData = await ReadPLCVariable('%s%PLC1.MAIN.motorStatus%/s%');
                        console.log(`BoolData = ${BoolData}`);                        
                        console.log(`Data point #2`);
                    }
                    catch (error) {
                        console.log(`error occured = $ {error}`);
                    }
                    console.log(`Data point #3`);
                }
                console.log(`Data point #4`);
                asyncMyCall();
                console.log(`Data point #5`);
            }

The output of the above function

Data point #1
Data point #4
Data point #5
myParameterData = true
BoolData = true
Data point #2
Data point #3

The point I see is that if we want to use manipulated variable by the async function we have to be careful when to use those variables. 

Lets see the following example.

var result = 0;
function resolveAfter2Seconds() {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve(20);
    }, 2000);
  });
}
async function asyncCall() {
  console.log('calling');
  const result = await resolveAfter2Seconds();
  console.log('result =' + result);
  return result;
}
var v = asyncCall();
console.log(v);

Output:

"calling"
[object Promise] { ... }
"result =20"

asyncCall print the calling and then return the promise object and finally the result is printed.

03: 

 An uncaught exception occurred in the processing of a JavaScript action

 Exception: SyntaxError: Unexpected identifier

12:  PLC array size change and HMI needs remapping

We have an array

myArray : ARRAY [0..9] OF INT

Now it has redefined

myArray : ARRAY [0..5] OF INT

In this case, myArray will not be available if we don’t remap myArray

13:  When we use then and async

If we don’t use async  then we need to  use then see the sample at section Get value by calling .then method

In the following code we use async keyword inside another function and we are not using .then()

function RefreshGridViewWithPLC(GridControl) {
	var readData;
	async function asyncCall() {
		readData = await ReadPlcData('%s%PLC1.MAIN.bigData%/s%');
		gtotalPLCLength = readData.length;
		var listBoxData = [];
		for (var i = 0; i < gtotalPLCLength; i++) {
			var emptyObject = {
				boolData: false,
			};
			emptyObject.boolData = readData[i].boolData;
			listBoxData.push(emptyObject);
		}
		GridControl.setSrcData(listBoxData);
	}
	try {
		asyncCall();
	} catch (error) {
		console.log(`ErrorCode Calling RefreshGridViewWithPLC = ${error}`);
	}
}