Q:

Will an es6 export changed after beeing exported be changed on import?

Will an es6 export changed after beeing exported be changed on import?  
For readability and to keep important stuff up top we think about using a file structure like:
export default myFunction;
myFunction.$inject = ['something'];
function myFunction(){
  //
}

But will the value defined for $inject be available on import by definition?
import myFunction from './myFunction';
if(myFunction.$inject)
// What value has myFunction.$inject ?

Is the imported file just imported up to the export statement? 
For our setup with Webpack and BabelJS the value seems to be set, but does that hold true for strict es6 interpretation?

A:

But will the value defined for $inject be available on import by definition?

Yes it will. But that has nothing to do with ES6 modules. Since objects (functions are objects) are represented as references, any mutation you are doing is visible everywhere else that has a reference to that object.

The more interesting aspect is this one:
// a.js
export var x = 42;
export function changeValue() {
  x = 21;
};

// b.js
import {x, changeValue} from './b.js';
console.log(x); // 42
changeValue();
console.log(x); // 21

Import and exports are live. That means that assigning a new value to an export will cause the import to update as well. You can think about this as assign by reference: The import binding does not have a copy of the exported value but a reference to the memory location of the export binding.

