Get to know more about the latest JS runtime

made by the creator of Node.js (Ryan Dahl)

DumbWays.id

Saturday, 11 July 2020

twitter.com/griko_nibras

Deno In A Nutshell

My name is Griko Muhammad Sultan Nibras
Or just Griko Nibras if it's too long
Remote software developer based on Toronto, Canada
SurabayaJS core organizer
Deno Land Indonesia contributor
Still haven't finished my thesis at ITATS
Just made this deck 12 hours before prime time

Hi there! 👋

This deck is about... 👨‍💻

What, who, and why Deno
Comparison of Deno vs Node.js
Simple code examples with interactive embeds

This deck isn't about... 🙅

Learning basic JavaScript (and TypeScript)
Replacing every Node.js app with Deno
(let's face it, Node.js isn't going anywhere)

Before we start... 🙇

I use Deno for fun; haven't made any heavy production apps
This slide is available at griko.dev/deno-dumbwaysid
Original link at slides.com/grikomsn/deno-in-a-nutshell

Now that's out of the way, let's start 👏

There's no programmer from other (programming) languages that can say

There's no programmer from other (programming) languages that can say "I have made a platform

There's no programmer from other (programming) languages that can say "I have made a platform, website

There's no programmer from other (programming) languages that can say "I have made a platform, website, mobile app

There's no programmer from other (programming) languages that can say "I have made a platform, website, mobile app, backends from database to business logics

There's no programmer from other (programming) languages that can say "I have made a platform, website, mobile app, backends from database to business logics only using one programming language

Rahmadani Ardhyanto, SurabayaJS Meetup #9 - 21 June 2020

There's no programmer from other (programming) languages that can say "I have made a platform, website, mobile app, backends from database to business logics only using one programming language" else than JavaScript.

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine
Ryan Dahl authored Node.js version 0.0.1 in May 2009
Isaac Z. Schlueter authored npm version 0.0.1 in January 2010
Dahl stepped aside and promote Isaac to manage Node.js in January 2012

Brief History of Node.js

JavaScript has changed significantly since Node.js was designed in 2009.

Package managers
Promises (async await)
ES Modules
Typed Arrays
TypeScript 👏🏻

And with changes, there are problems with Node.js...

10 Things I Regret About Node.js (6 June 2018)

Ryan Dahl at JSConf EU 2018 (youtube, slide pdf)

10 Things I Regret About Node.js (6 June 2018)

Ryan Dahl at JSConf EU 2018 (youtube, slide pdf)

Ryan Dahl, JSConf EU 2018

It could have been much nicer.

I see bugs that I introcuded that aren't really bugs-- they're just how it works, but they are bugs. And they were design mistakes that cannot be corrected because there's so much software that uses it.

Regret #1: Promises 💁🏻‍♂️

Ry added Promises in June 2009
...but removed in February 2010 :(
Initial idea was to keep it minimal
Many async APIs aged badly due to this

const { readFile, readFileSync } = require("fs");

// old async api with callback
readFile("/some/file/path", {}, (err, buffer) => {
  // ...
});

// synchronous api
const buffer = readFileSync("/some/file/path", {});

Example Node.js "fs" APIs

const { readFile } = require("fs/promises");

// new async api from fs/promises
readFile("/some/file/path", {})
  .then((buffer) => {
    // ...
  })
  .catch((err) => {
    // ...
  });

// new async api from fs/promises using await
const bufferAsync = await readFile("/some/file/path", {});

Example Node.js "fs/promises" APIs

https://brunolm.wordpress.com/2017/01/13/using-asyncawait-in-typescript-javascript/

Regret #2: Security Concerns 🔐

V8 itself is a very good security sandbox
Node.js has access to all system calls
So by default, any script can access the network, disk, and so on
By nature, a linter should not be able to access your files and network

Regret #3: Complicated Build System 🔥

Chrome's V8 started using GYP, which Node.js follows
...but then Chrome dropped GYP for GN, leaving Node.js the sole GYP user
Awful experience for devs (think JSON files but in Python)
Various Node.js wrappers for GYP (eg. node-gyp)

Regret #4: package.json 📚

Node.js `require` to inspect package.json for "main" file
Centralized package distribution (npm)
npm database 👉🏻 node_modules 👉🏻 package.json 👉🏻 script
Having a package.json creates the concept of a "module" as a directory of files (which does not exist on the web)
Has various unnecessary metadata (boilerplate noise)

Regret #5: node_modules 📦

Vendoring by default semantics; modules are installed locally
Complicates the module resolution algorithm
Deviates from browser semantics

Regret #6: require without extension 📝

Node.js JavaScript !== Browser JavaScript
Module loader has to query filesystem to guess the intended import
Needs extra steps to resolve module (checking file extension and so on)

Regret #7: index.js 🔖

"I thought it was cute, because there was index.html" 😂
Complicates the module loading system
Unnecessary after require supported package.json

Regret #8: ...?

Ryan Dahl, JSConf EU 2018

When you're designing a program, there are things that you think might be cute to add. You always regret those.

If those are unnecessary and simply cute, don't do them.

And with that, Ry introduced to the world an early prototype of Deno ✨

Made also using Chrome's V8 JavaScript engine
Early prototype was made using Golang
Repository: github.com/ry/deno
Initial commit: github.com/ry/deno/commit/f7c5e190819

Fast forward to 13 May 2020...

Deno 1.0 was released! 🎉

https://deno.land/v1

What is Deno?

JavaScript/TypeScript runtime
Tech used:
- V8
- TypeScript
- Rust
- Tokio (event loop)

https://deno.land/manual/introduction#introduction

Why "Deno"? 🤔

Anagram of "node" -> "deno"
...or this 👇🏻

Why create Deno?

We want a fun and productive system from scripting. Neither Node.js nor Python or Ruby are satisfactory.

Ryan Dahl & Kitson Kelly, TSConf 2019

Deno Goals 🥅

Utilize the fact that JavaScript is a secure sandbox
- No filesystem/network/etc. access by default 🤯
- Opt-in via runtime flags (e.g. --allow-env)
Ship with TypeScript compiler 🤯🤯
Simplify the module system
- No Node.js compatibility
- Imports are only relative or absolute URLs 🤯🤯🤯
Imports must include file extension
Remote files are fetched and cached indefinitely
- Use --reload to refetch
Vendoring can use non-default cache directory

Deno Goal: Simplify the module system 📦

// import remotely
import { serve } from "https://deno.land/std@0.60.0/http/server.ts"; // ✅
import { serve } from "https://deno.land/std/http/server.ts"; // ✅
import { Airtable } from "https://denoland.id/x/airtable@v0.2.1/mod.ts"; // ✅

// import locally
import { example } from "./some/directory/mod.ts"; // ✅
import { example } from "./some/directory/mod"; // ❌

Module == File == URL