What is Shallow cloning or merging objects

Question

In ES6

Answer 1

Shallow cloning means the variables value is stored in the same location. Merging objects means to make two objects a single object using merge() method

Answer 2

An example:

let a = { info: { name: "joe" } }

now let's copy `a`, by making a new object that contains a.x:

let b = { info: a.info } // or alternatively
let b = { ...a }

That's a shallow copy. What does that mean?

Consider

b.info.name = "mary";

What happened to `a`?

console.log(a);
>>> { info: { name: "mary" } }

So changing b.info.name changed a.info.name. That's because a.info and b.info point to the same object.

But check this:

b.info = "not available"
console.log(a);
>>> { info: { name: "mary" } }

So that did not change a.info because we pointed b.info to another object.

And that's it, when you do something like

b = { ...a }

in ES6, it copies the object, but only "one layer deep".

Try it out in the code playground to wrap your head around it.

I see you did the C++ course, if you know about pointers this should make a lot more sense.