Deh, Deh...Deno
A secure runtime for JavaScript and TypeScript.
What is Deno?
- It's like NodeJs
- Deeply improved in many ways
- Was announced in Jun 6, 2018 By Ryan Dahl as JSConf EU
Probably every talk about Deno begins like this
deno run https://deno.land/std/examples/welcome.tsdeno repl
Deno 1.5.3
exit using ctrl+d or close()
>REPL ( read–eval–print loop)
Static file
Why start this project?
- No Promise API
- Security/Sandbox
- Build system (GYP)
- NPM (bundled in node & package.json)
- node_modules (not isomorphic, algorithm resolution, etc)
- require() without the extension
- ....
- Type script
Accorning to Ryan Dahl
...go and see the video
Let's talk about features
- Also, build on top of V8
- Modern features of javascript
- Has an extensive standard library
- Typescript at its core (no need for tsc, ts-node, etc.)
- Default ES modules (no esm, not experimental flags, no babel...)
- No Package Manager (no NPM)
- Wait! What?!?!?
- First-class await (frigging finally...)
- Built-in testing capabilities
- Isomorphic features - aims to be browser-compatible (built-in fetch, window)
- Integrated tooling
- More to come
const raw = await fetch('https://jsonplaceholder.typicode.com/users');
const asJson = await raw.json();
console.info(asJson);
Check this...
Is something strange? Missing?
- Node API was initially callback-based
- Then we got Promises
- Then we got promisify()
- Then we got Async await
- Now we have first class await
Kewl...? so why switch?
- Check the video
- NPM is not secured
- Typescript is great
- We did some early mistakes (callback)
Node killer?
- No
- They work together - influence each other
- Node is here to stay - it's huge
Similar
- V8 Chromium
- A runtime environment for javascript
- Written in C++ and Javascript
- Official package manager (NPM)
- Used CommonJS - require()
- No Sandboxing
- No single executable
Different
- Written in Rust and Typescript
- No package manager
- ES6 module support
- Sandboxing as a default
- A single executable
No NPM
- Rely on GitHub scripts
- The good
- Very flexible
- No need to publish
- The bad
- Might not be reliable
- To fix this you can use https://deno.land/x
Lets demo this
No centralized package manager
Tools
deno --help
deno 1.5.3
A secure JavaScript and TypeScript runtime
Docs: https://deno.land/manual
Modules: https://deno.land/std/ https://deno.land/x/
Bugs: https://github.com/denoland/deno/issues
SUBCOMMANDS:
bundle Bundle module and dependencies into single file
cache Cache the dependencies
completions Generate shell completions
doc Show documentation for a module
eval Eval script
fmt Format source files
help Prints this message or the help of the given subcommand(s)
info Show info about cache or info related to source file
install Install script as an executable
lint Lint source files
repl Read Eval Print Loop
run Run a program given a filename or url to the module. Use '-' as a filename to read from stdin.
test Run tests
types Print runtime TypeScript declarations
upgrade Upgrade deno executable to given versionfmt
test
bundle
deno server
import { serve } from 'https://deno.land/std@0.80.0/http/server.ts';
const HTTP_OK = 200;
const DEFAULT_PORT = 8080;
const server = serve({ hostname: '0.0.0.0', port: DEFAULT_PORT });
console.log(`HTTP webserver running. Access it at: http://localhost:8080/`);
for await (const request of server) {
let bodyContent = 'Your user-agent is:\n\n';
bodyContent += request.headers.get('user-agent') || 'Unknown';
bodyContent += `\nroute: ${request.url}`;
const body = Array.from(request.headers.keys()).reduce((acc, value) => {
return `${acc}\n${value}: ${request.headers.get(value)}`;
}, bodyContent);
request.respond({ status: HTTP_OK, body });
}
vscode extention
Native modules
Popular servers
Github
Documentation
Performance
The end
...or is it?
Deh, Deh...Deno
By Eyal Mrejen
