class-style "this.handleImagePicked" and undeclared function/variable assignments in with-aws-storage-upload

https://github.com/expo/examples/blob/master/with-aws-storage-upload/App.js

Could someone explain if this code was supposed to be for class based components or something? I am getting errors for property not existing:

handleImagePicked = async (pickerResult) = -- [Link to line 53](https://github.com/expo/examples/blob/356907aeb82d35bc0f8e443aa3f69f940a840666/with-aws-storage-upload/App.js#L53C3-L53C45)

uploadImage = (filename, img) => {

Why aren't they defined with const or let or var like const uploadImage = (filename, img) => {...? Also why do we have this.handleImagePicked(result); inside takePhoto and pick pickPhoto functions?

I haven't yet connected with amazon aws. I actually want to use Firebase instead. I don't think `handleImagePicked` and others are coming as global variables from some import.