#js runtimes

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JavaScript runtimes are environments in which JavaScript code is executed. They provide an interface for developers to write code and interact with the underlying operating system, allowing them to create dynamic webpages and applications. The most popular JavaScript runtime is the browser, but there are also server-side runtimes such as Node.js and Deno.js, which allow developers to write server-side code in JavaScript.
How Bun Makes Building React Apps Simpler & Faster
React Day Berlin 2022React Day Berlin 2022
9 min
How Bun Makes Building React Apps Simpler & Faster
Bun’s builtin JSX transpiler, hot reloads on the server, JSX prop punning, macro api, automatic package installs, console.log JSX support, 4x faster serverside rendering and more make Bun the best runtime for building React apps
Node.js Compatibility in Deno
Node Congress 2022Node Congress 2022
34 min
Node.js Compatibility in Deno
Can Deno run apps and libraries authored for Node.js? What are the tradeoffs? How does it work? What’s next?
What's New on Node.js Test Runner and Why it's Game-changing
Node Congress 2024Node Congress 2024
17 min
What's New on Node.js Test Runner and Why it's Game-changing
Node's new test runner is pretty cool but not many people are using it yet. In my talk, I'll show you all the neat stuff it can do, including some features I worked on. We'll take a look under the hood of Node to see how mocks work and how to use them. I'll also chat about what's next for the runner and what to expect down the line. Get ready to up your testing game with native assertions and keep things running fast!
Testing Alternative Runtimes with Node and Vitest
Node Congress 2024Node Congress 2024
25 min
Testing Alternative Runtimes with Node and Vitest
A deep dive into how we built support for running Vitest tests in the Cloudflare Workers runtime. We'll start by giving an overview of the Cloudflare developer platform, including our open-source workerd JavaScript runtime and local simulator Miniflare. Next we'll talk about how Vitest works and provides support for custom runtimes, using Node.js as a driver to run tests in another environment. We'll describe the specifics of our custom Vitest pool, and how we added support for dynamic code evaluation to our runtime. Finally we'll talk about how we improved developer ergonomics with isolated per-test storage, test helpers for accessing Durable Object instances directly, and support for declarative HTTP request mocking., and how we created a service to build types for users' specific compatibility settings.
Roll you own JavaScript runtime
Node Congress 2023Node Congress 2023
21 min
Roll you own JavaScript runtime
In this talk, we’ll create a small JavaScript runtime from scratch in Rust. We’ll leverage the same ecosystem of components that Deno uses to show that rolling a bespoke runtime fitting your needs is simple and fun in 2023
Eval all the strings! - Hardened JavaScript
Node Congress 2023Node Congress 2023
8 min
Eval all the strings! - Hardened JavaScript
This talk is about SecureEcmaScript and Compartments which are TC39 proposals, and I'm working on tooling to make these concepts usable with people championing those proposals.
This is a first-hand account of the future of JavaScript security.
SES + tooling (LavaMoat or Endo) is making limiting access to network, fs, core modules or globals possible on a per-package basis.
I want to show how they work, what possibilities they open and how to make that future happen today with some effort.
To me this is the final step in securing npm supply chain - even if a package gets taken over by bad actors, it won't be able to hurt me.
Bun, Deno, Node.js? Recreating a JavaScript runtime from Scratch - Understand magic behind Node.js
Node Congress 2023Node Congress 2023
29 min
Bun, Deno, Node.js? Recreating a JavaScript runtime from Scratch - Understand magic behind Node.js
Bun, Deno, and many other JavaScript runtimes have been hyped, but do you know why? Is it that easy to make a runtime from scratch?

I've been researching the secret behind Node.js' power and why there are so many new JavaScript runtimes coming up. Breaking down each key component used on Node.js I've come to interesting conclusions that many people used to say whereas in practice it works a bit differently.

In this talk, attendees will learn the concepts used to create a new JavaScript runtime. They're going to go through an example of how to make a JavaScript runtime by following what's behind the scenes on the Node.js project using C++. They'll learn the relationship between Chrome's V8 and Libuv and what makes one JavaScript runtime better than others.

This talk will cover the following topics:
- What's a JavaScript Engine - V8
- Why Node.js uses Libuv
- How to create a JS Runtime from scratch
Instant websites using Fresh and Deno on the Edge
React Advanced Conference 2022React Advanced Conference 2022
33 min
Instant websites using Fresh and Deno on the Edge
Any interaction faster than 100ms is imperceptible to users - what if all website interactions, including loading were 100ms or less? Let's explore strategies and how Fresh & Deno can help.
The Future of JavaScript Runtimes
Node Congress 2022Node Congress 2022
34 min
The Future of JavaScript Runtimes
JavaScript was born in the browser, Node brought it to the server embracing unix primitives and async I/O and lately Cloudflare Workers & Deno Deploy have brought it to the edge. Let’s take a look at where JavaScript runtimes are heading and how it will shape the software we write.