In JavaScript.

How do I add an object to an existing object?

For example, I have an object called target, where: let target = { "0": { "name": "Bob", "age": "22", "sex": "male", "id": "0" }, "1": { "name": "John", "age": "32", "sex": "male", "id": "1" } };

and another object called source, where: let source = { "name": "Sue", "age": "30", "sex": "female" };

I have tried using Object.assign(), but it just adds Sue as is.

My desired results would be:

"0": { "name": "Bob", "age": "22", "sex": "male", "id": "0" },

"1": { "name": "John", "age": "32", "sex": "male", "id": "1" },

2: { name": "Sue", "age": "30", "sex": "female" id: 2 }

where the numbers increment whenever something is added to the object and has the same format.