const source = { a: 1, b: { c: 2 } };
const target1 = Object.assign({}, source);
const target2 = { ...source };

source.b.c = 99;
target1.a = 10;
target2.b.c = 50;

console.log(source.a);
console.log(source.b.c);
console.log(target1.a);
console.log(target1.b.c);
console.log(target2.a);
console.log(target2.b.c);