What you need to start with Deno

Updated 2 years ago 11 min read

#Deno #Typescript #Tutorials #web development

Table of contents

Section 1: Deno Foundations

4. Why Deno?

Deno
Rust by Mozilla
TypeScript by Microsoft
V8 Engine by Google

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5. Deno Runtime And V8 Engine

JS / TS -> V8 Engine -> Mobile / Web

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6. Deno Installation

curl -fsSL https://deno.land/x/install/install.sh | sh

Deno was installed successfully to /Users/chesterheng/.deno/bin/deno
Manually add the directory to your $HOME/.bash_profile (or similar)
- export DENO_INSTALL=“/Users/chesterheng/.deno”
- export PATH=“$DENO_INSTALL/bin:$PATH”

open /Users/chesterheng/.deno/bin/deno
/Users/chesterheng/.deno/bin/deno --help
deno

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7. Quick Note: Installing Deno

Deno online editor

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10. Setting Up Our Developer Environment

deno run deno.js
deno run deno2.ts

deno.js

const food = Deno.args[0];
const parent = Deno.args[1];

if (food === 'love' && parent === 'ryan') {
  console.log('🦕...Deno is born!')
} else {
  console.log('🥚...this egg needs some love')
}

setTimeout(() => {
  console.log('check')
}, 1000)

console.table(Deno.metrics())

deno2.ts

const b: string = 'Chester'
console.log(b)

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11. Quick Note: Official VS Code Plugin

Download and enable Visual Studio Code Deno extension
Enable Deno for your project:
- Create a file .vscode/settings.json in your project folder:
```
{
"deno.enable": true
}
```

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12. Our First Deno App

deno run deno.js 'love'

deno.js

const food = Deno.args[0]

if(food === 'love') {
  console.log('🦕...Deno is born!')
} else {
  console.log('🥚...this egg needs some love')
}

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13. Exercise: Our First Deno App

deno run deno.js 'love' 'ryan'

deno.js

const food = Deno.args[0];
const parent = Deno.args[1];
if (food === 'love' && parent === 'ryan') {
   console.log('🦕...Deno is born!')
}

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15. Deno Internals And Architecture

	Node JS	Deno
Engine	V8	V8
Written In	C++	Rust
Asynchronous I/O	LIBUV	TOKIO

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17. Deno Metrics

deno run deno.js

deno.js

setTimeout(() => {
  console.log('check')
  console.table(Deno.metrics())
}, 1000)

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18. Exercise: Deno Architecture

When do we run the Rust code?

Deno.
window.

	Node JS	Deno
Window Object	global	window
window.fetch	node-fetch	available

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Section 3: Deno vs Node

21. Deno Game Changers

Deno

First class TypeScript

ES Modules

import "https://deno.land/std@0.65.0/examples/welcome.ts"
import "https://deno.land/std@0.65.0/examples/chat/server.ts"

Security first
```
deno run --allow-net deno2.js
```
“Decentralized” modules: developer can host modules anywhere ->
Standard Library
Built In Tooling
Browser Compatible API
- JS can run in browser with no changes
- same window object with browser
- fetch is available
Single Executable: deno
Async returns Promises
Opinionated Modules: Deno Style Guide

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24. Single Executable To Rule Them All

“deno compile” into executable

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25. Deno Security

Permissions for CLI

pub allow_read: PermissionState,
pub read_allowlist: HashSet<PathBuf>,
pub allow_write: PermissionState,
pub write_allowlist: HashSet<PathBuf>,
pub allow_net: PermissionState,
pub net_allowlist: HashSet<String>,
pub allow_env: PermissionState,
pub allow_run: PermissionState,
pub allow_plugin: PermissionState,
pub allow_hrtime: PermissionState,

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26. Deno Permissions

Whitelisting is the practice of explicitly allowing some identified entities access to a particular privilege, service, mobility, access or recognition. It is the opposite of blacklisting.
Drake — a task runner for Deno

deno run --allow-net deno2.js
deno run --allow-env main.ts
deno run --allow-all main.ts
deno run -A main.ts
deno run -help
deno install --allow-env main.ts
section-03
deno run -A Drakefile.ts hello

deno2.js

import "https://deno.land/std@0.65.0/examples/welcome.ts"
import "https://deno.land/std@0.65.0/examples/chat/server.ts"

Drakefile.ts

import { desc, run, task, sh } from "https://deno.land/x/drake@v1.2.6/mod.ts";

desc("Minimal Drake task");
task("hello", [], async function() {
  console.log("Hello from Drake!");
  await sh("deno run --allow-env main.ts");
  await sh("echo Hello World");
});

run()

main.ts

console.log("Hello", Deno.env.get("USER"));

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Section 4: Deno Modules And Tooling

29. How Modules Work In Deno

deno info deno3.js

local: deno3.js
type: JavaScript
deps:
deno3.js
  └── deno2.js

deno2.js

export function denode(input) {
  if (input.toLowerCase() === 'node') {
    return input.split("").sort().join("")
  }
  return input;
}

deno3.js

import { denode } from './deno2.js'

console.log(denode("NODE"));

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30. URL Modules

deno info deno3.js

Download https://deno.land/std@0.66.0/examples/welcome.ts
local: deno3.js
type: JavaScript
deps:
deno3.js
  ├── deno2.js
  └── https://deno.land/std@0.66.0/examples/welcome.ts

deno info https://deno.land/std@0.66.0/examples/welcome.ts

local: /Users/chesterheng/Library/Caches/deno/deps/https/deno.land/aaa5f7b759111e731af7b564810dc454f6ecbeb452c020834e6e6782a3fd973e
type: TypeScript
compiled: /Users/chesterheng/Library/Caches/deno/gen/https/deno.land/aaa5f7b759111e731af7b564810dc454f6ecbeb452c020834e6e6782a3fd973e.js
deps:
https://deno.land/std@0.66.0/examples/welcome.ts

deno2.js

export function denode(input) {
  if (input.toLowerCase() === 'node') {
    return input.split("").sort().join("")
  }
  return input;
}

deno3.js

import { denode } from './deno2.js'
import "https://deno.land/std@0.66.0/examples/welcome.ts"

console.log(denode("NODE"));

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31. Standard Library

Deno Standard Library
Inspired by Go
Maintained by Deno team
Dependencies are with the standard library

deno info https://deno.land/std/http/server.ts

Download https://deno.land/std/http/server.ts
Warning Implicitly using latest version (0.66.0) for https://deno.land/std/http/server.ts
Download https://deno.land/std@0.66.0/http/server.ts
Download https://deno.land/std@0.66.0/encoding/utf8.ts
Download https://deno.land/std@0.66.0/io/bufio.ts
Download https://deno.land/std@0.66.0/_util/assert.ts
Download https://deno.land/std@0.66.0/async/mod.ts
Download https://deno.land/std@0.66.0/http/_io.ts
Download https://deno.land/std@0.66.0/async/deferred.ts
Download https://deno.land/std@0.66.0/async/delay.ts
Download https://deno.land/std@0.66.0/async/mux_async_iterator.ts
Download https://deno.land/std@0.66.0/async/pool.ts
Download https://deno.land/std@0.66.0/textproto/mod.ts
Download https://deno.land/std@0.66.0/http/http_status.ts
Download https://deno.land/std@0.66.0/bytes/mod.ts
local: /Users/chesterheng/Library/Caches/deno/deps/https/deno.land/41079ae77abd890bc4e9a389c6b449dda2f6c8e75955df8af2ff39094c277f04
type: TypeScript
compiled: /Users/chesterheng/Library/Caches/deno/gen/https/deno.land/41079ae77abd890bc4e9a389c6b449dda2f6c8e75955df8af2ff39094c277f04.js
deps:
https://deno.land/std/http/server.ts
  ├── https://deno.land/std@0.66.0/encoding/utf8.ts
  ├─┬ https://deno.land/std@0.66.0/io/bufio.ts
  │ ├── https://deno.land/std@0.66.0/bytes/mod.ts
  │ └── https://deno.land/std@0.66.0/_util/assert.ts
  ├── https://deno.land/std@0.66.0/_util/assert.ts
  ├─┬ https://deno.land/std@0.66.0/async/mod.ts
  │ ├── https://deno.land/std@0.66.0/async/deferred.ts
  │ ├── https://deno.land/std@0.66.0/async/delay.ts
  │ ├─┬ https://deno.land/std@0.66.0/async/mux_async_iterator.ts
  │ │ └── https://deno.land/std@0.66.0/async/deferred.ts
  │ └── https://deno.land/std@0.66.0/async/pool.ts
  └─┬ https://deno.land/std@0.66.0/http/_io.ts
    ├── https://deno.land/std@0.66.0/io/bufio.ts
    ├─┬ https://deno.land/std@0.66.0/textproto/mod.ts
    │ ├── https://deno.land/std@0.66.0/bytes/mod.ts
    │ └── https://deno.land/std@0.66.0/encoding/utf8.ts
    ├── https://deno.land/std@0.66.0/_util/assert.ts
    ├── https://deno.land/std@0.66.0/encoding/utf8.ts
    ├─┬ https://deno.land/std@0.66.0/http/server.ts
    │ ├── https://deno.land/std@0.66.0/encoding/utf8.ts
    │ ├── https://deno.land/std@0.66.0/io/bufio.ts
    │ ├── https://deno.land/std@0.66.0/_util/assert.ts
    │ ├── https://deno.land/std@0.66.0/async/mod.ts
    │ └── https://deno.land/std@0.66.0/http/_io.ts
    └── https://deno.land/std@0.66.0/http/http_status.ts

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32. 3rd Party Modules

Deno Third Party Modules
Deno do not support CommonJS
Deno need to know the file extension

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33. Deno Caching

Linking to third party code

open $HOME/Library/Caches/deno

deno run deno3.js

Download https://deno.land/std@0.66.0/examples/welcome.ts
Check deno3.js
Welcome to Deno 🦕
DENO

deno run deno3.js

Check deno3.js
Welcome to Deno 🦕
DENO

deno run --reload deno3.js

Download https://deno.land/std@0.66.0/examples/welcome.ts
Check deno3.js
Welcome to Deno 🦕
DENO

What you need to start with Deno

Section 1: Deno Foundations

4. Why Deno?

5. Deno Runtime And V8 Engine

6. Deno Installation

7. Quick Note: Installing Deno

10. Setting Up Our Developer Environment

11. Quick Note: Official VS Code Plugin

12. Our First Deno App

13. Exercise: Our First Deno App

15. Deno Internals And Architecture

17. Deno Metrics

18. Exercise: Deno Architecture

Section 3: Deno vs Node

21. Deno Game Changers

24. Single Executable To Rule Them All

25. Deno Security

26. Deno Permissions

Section 4: Deno Modules And Tooling

29. How Modules Work In Deno

30. URL Modules

31. Standard Library

32. 3rd Party Modules

33. Deno Caching

35. NPM for Deno

36. Managing Module Versions

37. Where the Bleep is package.json?

38. Deps.ts

39. Locking Dependencies

40. Deno Upgrade

41. Reviewing Deno Modules

42. Deno Tooling

Section 5: TypeScript

Section 6: Deno File I/O