All language subtitles for 004 Exports and Imports_en

Another feature which next generation javascript offers is about writing modular code so javascript

code you split up over multiple files.

And obviously we already can split our code over multiple files.

We just have to import them in the correct order in our html files.

And the idea behind export and import statements and so-called modules is that inside of a javascript

file we can import content from another file so that the javascript files themselves know their

dependencies.

It might look like this.

We have one file, person.js and there we have this constant person which is stored as a javascript object

and then this is the interesting part.

We export this the default keyword this is a special keyword marking this as the default export of

this file and we can then import this somewhere else and the import statement will be shown in a second.

We also might have a number of files where we export multiple things, here a constant named clean which

holds a function at the end and baseData which holds a number in a third file.

We might need to import from person.js and utility.js so app.js requires import statements.

And here are a couple of different import syntaxes you will see in this course. person.js as you see

uses the default keyword, the default keyword simply means if we just import something from that file

it will always be our default export.

So in this case the person constant therefore in import person from person.js we can name person whatever

we want, which is why I printed it twice here, person or prs doesn't matter.

It always refers to the thing you marked as the default with the default keyword. For utility.

js it's a bit different. There

We import from two different constants and therefore the import syntax uses the curly braces to explicitly

target specific things from that file.

These are so-called named exports because we import the stuff by its name.

We import the clean constant by its name and we import baseData by its name because we didn't mark anything

as the default.

So for javascript to know what exactly we're pointing to, we need to give it the exact name and the name

goes between curly braces.

By the way, you could also write this as one import statement with baseData comma clean or the other

way around.

So these are imports and exports.

You write all of this in your javascript files and will heavily use this throughout this course.

Now as with all these next generation javascript features, it won't run like this in all browsers.

Not even the most modern browsers support all the features we'll use in this project.

Therefore in the next course module I'll also show you how to quickly set up a project which in the

end just compiles all these next generation javascript features to current gen javascript features

so that we as a developer can use the next generation javascript without us shipping code that runs

nowhere.

So back to the imports and exports.

This is the syntax we use and you will see getting used a lot in this course.

You might also see some variations because we can also write this differently when we have a default

export.

You already saw that person is name you can choose totally on your own.

It doesn't matter here if you use person or prs.

If you have a named export you actually have to use the exact name defined in the file with the export

keyword.

Still what you can do.

You can assign an alias which you then again can freely choose in the file you are importing it with

the as keyword or if you have multiple named exports in a file.

You can import everything with this * special character and then assign an alias and bundled.

In this case would be a javascript object which exposes all constants and whatever you export in the other

file as properties so that you simply have bundled.baseData, bundled.clean to access the

export of things.

That's up to you and you will see me use these things throughout the course.

The most common use search is the top one.

Import curly braces something curly brace from.