Jarred Sumner
@jarredsumner
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building @bunjavascript. formerly: @stripe (twice) @thielfellowship. high school dropout. npm i -g bun
San Francisco, CA
Joined May 2014
Introducing Bun - an incredibly fast all-in-one JavaScript runtime.
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In the next version of Bun. You can compile and run C in JavaScript.
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wonder how many collective hours of time humanity has wasted because Map and Set use .size instead of .length
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Downloading 7,000 24 KiB files in parallel from S3 in us-east-1. left: Bun v1.1.44 with Bun's S3 client.right: Node v23.6.0 with AWS SDK v3
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from bun's discord. importing a Rust function in TypeScript via Bun plugin (tr1ckydev)
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50,000 ⭐️ & trending on GitHub today . ❤️ thank you for filing issues, I promise we will fix stuff
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in the next version of Bun. A memory leak impacting fetch() is fixed. left: bun v1.0.4.right: bun v1.0.5
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unix: seconds since 1970.windows: how many 100 nanosecond intervals has it been since the year 1601?
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Introducing bunx. auto-install & run an executable from npm. 100x faster than npx. left: "bunx esbuild --version" (1k runs).right: "npx esbuild --version" (1k runs)
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little-known fact. when you run eval() it calls JSON.parse first to check if it’s just json.
Why does everyone use JSON.parse() when eval() is way fewer characters?.
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Calling fetch(url) 15,000 times, in batches of 50 . left: Bun v1.1.7.right: Node v22
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Bun started as a frontend bundler. Bun became a runtime initially to make Next.js SSR work using Bun’s bundler . Over the next few weeks, we are going to unify Bun’s bundler and Bun’s runtime into a single tool. A full-stack JavaScript runtime.
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I’m still waiting for people to be more negative about Bun. People are too nice rn.
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This Ruby on Rails error page from 2013 is still better than every JavaScript server error page I’ve seen
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Open-source is built on the shoulders of giants. Bun wouldn’t have existed without Node.js and Node.js maintainers like @jasnell @matteocollina @yagiznizipli and so many more.
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X is using Bun in production!.
This was also the first production deployment of @bunjavascript at X. We chose Bun because it is the most performant and developer-friendly JavaScript runtime in our testing. We released the portal built on this system to all users at X, and the system handled it gracefully.
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Introducing the Bun Bundler. A fast JavaScript bundler deeply integrated into Bun's runtime .
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1 line fix 🫠
have spent at least 36 hrs (over a few days) debugging why the “bcrypt” package doesn’t work in bun.
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In the next version of Bun. Bun won't error when package.json has comments or trailing commas
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the right side and the left side will look a lot more similar in less than a year.
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bun install
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Early benchmark from a new JavaScript bundler. It transpiles JSX files:.- 3x faster than esbuild.- 94x faster than swc.- 197x faster than babel
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The implementation of bun install is hard mode. Nearly everything is linearly serializable. We avoid pointers because arrays might resize causing an invalid pointer, so we use byte offsets into a single buffer and a “string builder” to count then allocate then append.
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Bun 1.0 comes out September 7th. To join the live-streamed event, see the link in the reply.
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In the next version of Bun . You can import sqlite databases
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this will make javascript competitive with go and rust at concurrency
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React Native’s JSI hasn’t been talked about enough — it lets you call C++ from JS with little overhead. Yesterday, I wrote a library to fetch a list of photos from the camera roll. react-native-camera-roll: 360ms.my library using the JSI: 15ms. 20x faster & runs synchronously.
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separation of concerns means you have to check 3 different places to answer “where is the code for this thing”.
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functional programming people love saying “pure” and “immutable”.
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10 JavaScript/TypeScript features I avoid:. ?.if .let.var.for .class.else .const.() => {}.function() {}. They’re not always a problem. But, they’re overused and can often be replaced by better alternatives. Here’s why I avoid each, and what I do instead… 👇.
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Our goals for the next 10 days:.- Ship Bun.S3, builtin S3 client with almost the same api as Bun.file.- Ship Bun.sql, builtin Postgres client (and MySQL slightly later).- Ship HTML loader for `bun build`, bundling JS & CSS from .html.- Get 100% of node’s http module tests to pass.
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Yeah I agree with this. Zig is great for performance-critical systems software, but most startups should use JS or TS. Everything takes longer to ship in systems languages.
I actually might lose credibility for this one, but I don't think startups should be using Rust, Zig, etc. unless the technical advantages are critical or even inherent to the product. Like, if Python, JS, etc. are even options, you should probably be using Python or JS!.
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Zig is an extremely productive systems language. I personally found it harder to be productive in Rust.
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In the next version of Bun. `Bun.randomUUIDv7()` returns UUID v7, which is a sorting & database-friendly UUID
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If this was Windows I would be running a virus scanner right now.
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i was a little surprised at the number of negative reactions to Bun.s3. is it because it wasn’t clear enough that there are many non-AWS S3-compatible object storage APIs? you haven’t had to write code that uploads or downloads files on a server? something else?.
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Introducing robobun . Run JS from GitHub issues and PRs by mentioning "@robobun" with a code block
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I feel like it’s rare for engineers with > 5 years of experience to still love writing lots of code.
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GitHub should let you react to lines of code in pr diffs.
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Every day, Bun gets closer to being a 100% compatible drop-in replacement for Node.js.
In the next version of Bun. All but 1 of the Node.js `zlib` module tests pass
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In the next version of Bun. Bun.serve() uses less memory. After 800k requests. Elysia.v1.0.4: 47 MB.v1.0.3: 71 MB. Fastify.v1.0.4: 114 MB.v1.0.3: 267 MB. Express.v1.0.4: 116 MB.v1.0.3: 167 MB
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TIL there are large performance differences between PostgreSQL and MySQL.
Comparing the read-only performance of MySQL and PostgreSQL with the same 128 hash partitions.
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I bet moving from Rust to TypeScript will make Prisma faster. NAPI overhead & event loop scheduling overhead is significant for DB drivers.
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today and yesterday were so fun. thank you all. this is just the beginning for bun.
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Bun v0.6.0. - New JavaScript Bundler (200x faster than webpack).- New JavaScript Minifier.- Standalone executables.- Show duration in "bun test" (for each test).- Faster node:fs writeFile() on Linux.- Many bugfixes.
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this is ideal code. you may not like it, but this is what peak performance looks like
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bun install support is the most upvoted idea of all time in the @vercel github org discussions page
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Bun implements JSX prop punning btw. const Foo = <div {boom} /> . Transpiles the same as. const Foo = <div boom={boom} />.
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my initials are JS.
CEO of the largest metal fabrication rollup ($500m/yr) is named Brian Steel
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We are getting > 50 issues per day and our team is currently 7 people. Really need to hire more engineers. Strong C/C++ or Zig background required. Please apply at
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@HSVSphere @gizmobly @ludwigABAP some advice for you. people learn more from building things than commenting on things. having lots of extremely strong negative opinions about unimportant stuff you don’t have much experience with is going to cause problems and lead to missed opportunities.
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The next version of Bun supports "recursive" in fs.readdir(). "test/" in bun's repo:. bun: 3.76ms.node: 154ms. That's 40x faster.
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@youyuxi Fixed.
The next version of Bun supports "recursive" in fs.readdir(). "test/" in bun's repo:. bun: 3.76ms.node: 154ms. That's 40x faster.
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We added S3 support to Bun because S3-compatible object storage services slowly became the internet’s filesystem API. The same APIs for reading & writing files in development should just work in production.
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The next version of bun gets a "copy as markdown" button for frontend/build errors. so you can more easily ask for help in discord/slack/github
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