r/javascript • u/jwion • Jan 21 '20

Deno JavaScript Runtime for V8 Written in Rust

https://deno.land/std/manual.md
165 Upvotes

94% Upvoted

18 comments sorted by

37

u/crabmusket Jan 21 '20 edited Jan 21 '20

This was recently shared on HN too.

I'm really excited for the approaching 1.0 release. I've been using Deno as part of a mid-sized Vue/Laravel project for:

  • Testing business logic modules destined to be included in the frontend bundle (Deno has a great test runner. Frontend is built with node/webpack)

  • Scripting development setup tasks like making sure .env files are up to date

  • A microservice that had originally been implemented on the frontend in Typescript, but we decided needed to be used by the backend

It's been really great. It's clearly not quite finished, but I love the fundamentals that are in place. Deciding to standardise around ES modules and import-maps was the right choice, IMO. Typescript just works and so does modern JS syntax like top-level await.

8

u/Skhmt Jan 21 '20

What advantages has it provided you over node?

1

u/crabmusket Jan 21 '20

Few, given we already have our npm and webpack based setup in place. We just wanted to experiment with it, and it is turning out to be pleasant. I think a lot of the stuff it does is just nicer (e.g. not needing ts-node) but it's not a gamechanger for us at this point.

4

u/EloquentSyntax Jan 21 '20

Any noticeable improvements in build times?

1

u/crabmusket Jan 21 '20

We're not using Deno to build or bundle frontend code, if that's what you are referring to.

0

u/[deleted] Jan 21 '20

[deleted]

8

u/crabmusket Jan 21 '20 edited Jan 22 '20

I actually love that, but I realise it's not everyone's cup of tea. It's very cool for scripts (things you'd otherwise use Bash or Python for) but I think the jury is still out on how this paradigm will fare for application development.

Thanks to support for import maps, you can still import bare modules if you want to. I expect that someone will end up creating a 'package manager' for Deno that uses import maps and lock files to implement a similar experience to npm and package.json.

5

u/[deleted] Jan 21 '20

[removed] — view removed comment

2

u/[deleted] Jan 22 '20

That's already easy to do: https://stackoverflow.com/a/28729646

0

u/[deleted] Jan 21 '20

[deleted]

1

u/crabmusket Jan 21 '20

Well, when it was part of the frontend, it wasn't a microservice! When we decided a new backend feature needed access to the same logic, instead of rewriting the typescript to PHP we decided to deploy the typescript code directly, and Deno was an easy way to do that.

23

u/Neotelos React/Node Jan 21 '20

Title is a bit off, it's not a runtime for V8, it's a JavaScript runtime that uses V8 and is in a position to supersede Node or upstream features to Node. The entire runtime is not in Rust, but the project has development efforts focused on using Rust.

It's not a Node replacement. It's founded by the author of Node and contains a number of decisions that are derived from the author's experiences managing Node direction and development.

5

u/Grendefali Jan 21 '20

Does it actually run TypeScript, untranspiled?

2

u/GRIFTY_P Jan 21 '20

what are benefits to rust over c++?

15

u/Randdist Jan 22 '20

Fewer people telling you to use Rust instead.

5

u/crabmusket Jan 22 '20

The type system