Object Destructuring I

This post is a bit of a reboot from an earlier:

Object Destructuring

Manav Misra ・ Oct 27 '20

#javascript #react #beginners

Destructuring ❓

Although this is not a standard English word, we could think 🧠 of it as dismantling or picking apart or as the opposite of structuring 🏗️ something.

Objects

Some languages have structs. In JS, we have these glorious things known as objects. It's amazing and incredibly flexible that we can just spin up a couple of {} and start adding 🔑s and values. 👏🏾

const person = {
  fname: "Mark",
  lname: "Galloway"
}

And to access our 🔑, it's dot notation, .: person.fname. 🆒

Back to Destructuring

If we need to access person.fname a lot, we can do like this one: const { fname } = person;.

Although when creating variables with const we can normally make up our own names, in this case, the name inside of {} must match the name of a property in person - else it will be undefined.

But, I Don't Like fname

Can't I Just Call It mickeyMouse?

Yes - but just b/c you can, doesn't mean that you should!

Nevertheless, here we go:

const person = {
  fname: "Mark",
  lname: "Galloway"
}

const {fname: mickeyMouse} = person;

mickeyMouse; // "Mark" - 🙄

So, we destructure a 🔑 by its name, then we can easily rename it to something else. This is especially handy when we retrieve JSON from a database that uses some other SQL naming conventions.

For example, we might get back something like: {"first_name": "Mark", "last_name": "Galloway"}.

After parsing into JS, and assigning to a variable such as person, we could do: const {first_name: fname} = person.

Next time (assuming there's enough 👀 on this post!) we'll see 👀 examples of using this with function parameters.