Question

I'm trying to access linkArray after I use it as a function. Right now I'm getting a Reference Error saying my linkArray is not defined. I've also tried to used let and var and I had the same error. How can I use that array in a different scope without getting that error? I checked if linkArray is correctly filled and it is. In javascript.

const linkArray = await page.evaluate(() => {
let setLinkArray = [];
let elements = document.getElementsByClassName('setStoreLink');

for (var element of elements){
let setLinkID = element.id;
setLinkArray.push(setLinkID);
}
return setLinkArray;
});

var doSomething = await page.evaluate(() => {
return linkArray;
});

Answer 1

Hi,
Please check what page.evaluate function is returning. You are assigning value to the linkArray which is returned by page.evaluate function.

In your case page.evaluate function not returning what your passing function returns.

Let's take example where I can reproduce your similar problem,

// let take example page is object having evaluate function
// evaluate method receives function normally we call it as callback function.
let page = {
evaluate: function(callback){
// evaluate execute the callback
callback();
}
}
// lets call page.evaluate with some dummy function which returns object with success key and value
let result = page.evaluate(()=>{
return {success: true};
});
// get the result from page.evaluate
let doSomething = page.evaluate(()=>{
return result;
})
// print the result
console.log(doSomething);

For the output is: undefined

Reason :
page.evaluate executes the callback function not returning any value. So result will set as undefined. And also on do something my passing function is returning result but page.evaluate is not returning it. So again do something is set to undefined.

To rectify this I'm adding return statement in page.evaluate function which will return result that is returned by callback(passing function)

Check this:

// let take example page is object having evaluate function
// evaluate method receives function normally we call it as callback function.
let page = {
evaluate: function(callback){
// evaluate execute the callback and returns result
  return callback();
}
}
// lets call page.evaluate with some dummy function which returns object with success key and value
let result = page.evaluate(()=>{
return { success: true};
});
// get the result from page.evaluate
let doSomething = page.evaluate(()=>{
return result;
})
// print the result
console.log(doSomething);

From above code check the underlined code.

Now output is : { success: true }

In your check the what page.evaluate is doing and returning.

Images:

1. Without return statement:

2. With return statement:

Hope you got what you want, if you have any doubts please comment below (don't forget add what page.evaluate is doing and returning). Cheers..:))