Avoid accessing the DOM directly

[oliverjam]

week10-AJ/src/components/adduser.js

Line 14 in 4888b86

let newValue = document.getElementById("username").value

Generally it's a good idea to let React manage the DOM. This means avoiding stuff like querySelector if you can.

There are two other ways I'd recommend to getting the value of inputs:

1. Use a submit handler on the form element. The submit event object will contain all the input's values (event.target.elements.inputName.value). As a bonus submit events fire when the user hits "Enter" in an input (which won't work if you're just listening for clicks on the button)
2. Use a controlled input to keep the value in state. That way you always have the value available as a JS variable in scope.