Local variable within Async Function gets overwritten in a promise.all loop

async function init() {
  const promises = myObjects.map(async myObject => {
    return myFunction(myObject);
  });
  const result = await Promise.all(promises);
}

async function myFunction(myObject) {
    let arrayA = [];
    
    functionBresponse = await functionB();  //Basic utility function to fetch some items
    arrayA = arrayA.concat(functionBresponse);

    const res = {"Completed": 200};
    return res;
}

I am using promise.all to ensure myFunction runs async for the myObjects array. The problem here is that the local variable arrayA gets overwritten by the most recent iteration. I have looked into closures and understand the basic concept. However, I am unsure how to use it here.