Mapping items fetched from API javascript

I am trying to map some items returned to me from a API using a class and constructor with javascript.

My question is what I am doing wrong, since the log before the mapping “Result before Map” logs out my array of items. But after my map I get nothing and everything in my constructor is undefined.

Im probably missing something simple but I am just trying this to do it without a framework using pure javascript in order to learn more 🙂

class Test {
  constructor(obj) {
    this.testValue = obj.testValue
  }
}

async function getItems() {
  const promises = []

  const response = (await fetch(url)).json()
  promises.push(response)

  const result = await Promise.all(promises)
  console.log('Result before Map:', result)
  const tests = result.map(test => new Test(test))
  console.log('Result after Map:', tests)
}