In this episode of Syntax, Scott and Wes bring you the long-awaited Deno show — what it is, what it replaces, how you can use it, and more! Deque - Sponsor Deque’s free axe browser extension helps developers instantly catch 50% of accessibility bugs while they code. It’s lightweight, easy-to-use, and has zero false positives. Get started for free at deque.com/axe. Sentry - Sponsor If you want to know what’s happening with your errors, track them with Sentry. Sentry is open-source error tracking that helps developers monitor and fix crashes in real time. Cut your time on error resolution from five hours to five minutes. It works with any language and integrates with dozens of other services. Syntax listeners can get two months for free by visiting Sentry.io and using the coupon code “tastytreat”. Mux - Sponsor Mux Video is an API-first platform that makes it easy for any developer to build beautiful video. Powered by data and designed by video experts, your video will work perfectly on every device, every time. Mux Video handles storage, encoding, and delivery so you can focus on building your product. Live streaming is just as easy and Mux will scale with you as you grow, whether you’re serving a few dozen streams or a few million. Visit mux.com/syntax. Show Notes 02:13 - What is it? A secure runtime for JavaScript and TypeScript Built by Ryan Dhal — same guy who initially built Node.js API is JS or TS out of the box 04:55 - Does it replace / what is it in relation to? Node It’s a replacement for Node.js Express Web Server Frameworks like Express will run on Deno, but Express itself won’t currently run because they are build on Node APIs https://github.com/oakserver/oak Serverless Deno can be used for anything, so it can be used for serverless functions, or a traditional web server Serverless, Deno and TypeScript with Brian Leroux React / Vue / Svelte These things are just JavaScript, so they should/will work in Deno. Deno will replace your tooling. More involved things like Next.js that require Node APIs won’t work until. https://alephjs.org/ SSR It comes with all browser APIs out of the box! Fetch Window + Add Event listener Webpack / Parcel / Snowpack Deno is a bundler Prettier Deno is a formatter TSC Deno is a TypeScript compiler and runtime ESLint Deno is a linter Jest Deno is a Test Runner NPM Deno is a package manager - it pulls in packages from URLs 14:51 - Modules ES modules from the start Modules are loaded from URLs Why? No package registry to worry about This is how the browser works Import from URL You can also specify it in the json file https://github.com/oakserver/oak/blob/main/deps.ts https://deno.land/ Fetch is built in! It’s a browser API, but who cares?! Browser APIs window.add event Listener Deno is event based, like the browser 20:10 - A nice standard library https://github.com/denoland/deno/tree/master/std 22:14 - WASM Deno can run WASM with the same APIs that the browsers can Node is doing this too (experimental) 25:06 - Multi-threading with Web Workers 26:13 - Speed It’s fast! They took everything they learned from Node - good and bad Built in Rust From what we understand: V8 is written in C++ Node is written in C, C++ and JavaScript How it talks to V8 - Rust sits in-between the JS runtime, and the C++ V8 runtime and communicates between the two. https://github.com/denoland/deno/blob/master/core/examples/hello_world.rs 29:44 - Security Sandboxed —allow-read —allow-net -allow-write https://deno.land/manual@v1.6.3/getting_started/permissions#permissions-list You can specify which dirs it can access 33:39 - Run from anywhere https://www.npmjs.com/package/npx Deno run https://cool.com/whatever.ts 37:43 - Async out of the box Everything is based on async + await / promises right away. No callback APIs, no promise wrapping. Top level await 38:53 - Node Compatibility