Merge imports into single object and export it

help
1

below files are stored in imports folder, i would like to extend A in main.js using multiple import files, and export it out

    // main.js
    A = {
        a : 0
    };
    
    import './b.js'
    import './c.js'
    ...
    
    export default A;

    // b.js
    import A from './main.js'
    
    A.b = 1;

    // c.js
    import A from './main.js'
    
    A.c = 2;

    // App.js
    import A from './main.js'
    
    console.log(A);

what i get in console.log(A) is { a : 0 }

how to extend A in main.js and while import to App.js, A will be extended to as per below

{
    a : 0,
    b : 1,
    c : 2
}

what i get in the browser

{
    b : 1,
    c : 2,
    default : {
        a : 0
    }
}

in terminal it logged

{ a : 0 }