Swap key with value JSON

Question

I have an extremely large JSON object structured like this:

{A : 1, B : 2, C : 3, D : 4}

I need a function that can swap the values with

Answer 1

Using ES6:

const obj = { a: "aaa", b: "bbb", c: "ccc", d: "ffffd" };
Object.assign({}, ...Object.entries(obj).map(([a,b]) => ({ [b]: a })))