Rob Palmer
@robpalmer.bsky.social
JavaScript Infrastructure & Tooling at Bloomberg. Co-chairing TC39. Likely to tweet tech stuff about JS & software performance. Opinions are my own.
Reposted by Rob Palmer
Did you know about the `/*@__NO_SIDE_EFFECTS__*/` annotation?
It tells bundlers that a function has no side effects so every call to it can be tree-shaken if the result is unused.
Most bundlers and minifiers support it today.
But there's a nuance most people miss 👇
It tells bundlers that a function has no side effects so every call to it can be tree-shaken if the result is unused.
Most bundlers and minifiers support it today.
But there's a nuance most people miss 👇
February 17, 2026 at 8:29 PM
Did you know about the `/*@__NO_SIDE_EFFECTS__*/` annotation?
It tells bundlers that a function has no side effects so every call to it can be tree-shaken if the result is unused.
Most bundlers and minifiers support it today.
But there's a nuance most people miss 👇
It tells bundlers that a function has no side effects so every call to it can be tree-shaken if the result is unused.
Most bundlers and minifiers support it today.
But there's a nuance most people miss 👇
Reposted by Rob Palmer
👀 Chrome 145 DevTools has Soft Navigation markers
Nice DX improvement for building SPAs
Nice DX improvement for building SPAs
February 17, 2026 at 12:32 PM
👀 Chrome 145 DevTools has Soft Navigation markers
Nice DX improvement for building SPAs
Nice DX improvement for building SPAs
Reposted by Rob Palmer
State of the Browser is a community event, and we are grateful to everyone who supports us by becoming an official supporter or volunteer at our event!
Today, we spotlight @igalia.com! They are one of our small supporters and have been supporting us for 2 years now. Thank you! 💜
Today, we spotlight @igalia.com! They are one of our small supporters and have been supporting us for 2 years now. Thank you! 💜
February 17, 2026 at 11:36 AM
State of the Browser is a community event, and we are grateful to everyone who supports us by becoming an official supporter or volunteer at our event!
Today, we spotlight @igalia.com! They are one of our small supporters and have been supporting us for 2 years now. Thank you! 💜
Today, we spotlight @igalia.com! They are one of our small supporters and have been supporting us for 2 years now. Thank you! 💜
Electrobun is a new cross-platform runtime for shipping desktop apps ✨
Electron mostly uses C++ to embed both Node.js & Chromium.
Electrobun uses Zig to to embed Bun and - like Tauri - relies on the OS default web renderer.
🔷 Write apps in TypeScript
🧱 Process isolation
⚖️ 12MB base install size
Electron mostly uses C++ to embed both Node.js & Chromium.
Electrobun uses Zig to to embed Bun and - like Tauri - relies on the OS default web renderer.
🔷 Write apps in TypeScript
🧱 Process isolation
⚖️ 12MB base install size
February 17, 2026 at 8:12 AM
Electrobun is a new cross-platform runtime for shipping desktop apps ✨
Electron mostly uses C++ to embed both Node.js & Chromium.
Electrobun uses Zig to to embed Bun and - like Tauri - relies on the OS default web renderer.
🔷 Write apps in TypeScript
🧱 Process isolation
⚖️ 12MB base install size
Electron mostly uses C++ to embed both Node.js & Chromium.
Electrobun uses Zig to to embed Bun and - like Tauri - relies on the OS default web renderer.
🔷 Write apps in TypeScript
🧱 Process isolation
⚖️ 12MB base install size
Reposted by Rob Palmer
❌🛢️ Unbarrelify v1.1.0 is out
Barrel file removal tool for JS & TS projects
Changelog:
→ Feat: always preserve root index.js/ts file
→ Docs: explain why certain barrel files are preserved: github.com/webpro/unbar...
github.com/webpro/unbar...
Barrel file removal tool for JS & TS projects
Changelog:
→ Feat: always preserve root index.js/ts file
→ Docs: explain why certain barrel files are preserved: github.com/webpro/unbar...
github.com/webpro/unbar...
February 11, 2026 at 8:50 AM
❌🛢️ Unbarrelify v1.1.0 is out
Barrel file removal tool for JS & TS projects
Changelog:
→ Feat: always preserve root index.js/ts file
→ Docs: explain why certain barrel files are preserved: github.com/webpro/unbar...
github.com/webpro/unbar...
Barrel file removal tool for JS & TS projects
Changelog:
→ Feat: always preserve root index.js/ts file
→ Docs: explain why certain barrel files are preserved: github.com/webpro/unbar...
github.com/webpro/unbar...
Reposted by Rob Palmer
The "export defer" TC39 proposal aims to introduce a similar optimization *at the language level*, so that you can rely on it in all the tools and environments that you might run your code with.
Just because you need one thing from a module, you shouldn't pay the cost of all the others!
Just because you need one thing from a module, you shouldn't pay the cost of all the others!
February 12, 2026 at 3:45 PM
The "export defer" TC39 proposal aims to introduce a similar optimization *at the language level*, so that you can rely on it in all the tools and environments that you might run your code with.
Just because you need one thing from a module, you shouldn't pay the cost of all the others!
Just because you need one thing from a module, you shouldn't pay the cost of all the others!
Reposted by Rob Palmer
Made a few updates to the post - specifically:
- es2025 target
- new library additions/updates
- deprecation of node10
bsky.app/profile/type...
- es2025 target
- new library additions/updates
- deprecation of node10
bsky.app/profile/type...
TypeScript 6.0 beta is now published!
This release brings
- inference improvements for functions
- updates to package.json 'imports'
- the Temporal APIs
- alignments for the upcoming TypeScript 7.0
- & more!
Try it today!
devblogs.microsoft.com/typescript/a...
This release brings
- inference improvements for functions
- updates to package.json 'imports'
- the Temporal APIs
- alignments for the upcoming TypeScript 7.0
- & more!
Try it today!
devblogs.microsoft.com/typescript/a...
Announcing TypeScript 6.0 Beta - TypeScript
Today we are announcing the beta release of TypeScript 6.0! To get started using the beta, you can get it through npm with the following command: npm install -D typescript@beta TypeScript 6.0 is a uni...
devblogs.microsoft.com
February 11, 2026 at 10:01 PM
Made a few updates to the post - specifically:
- es2025 target
- new library additions/updates
- deprecation of node10
bsky.app/profile/type...
- es2025 target
- new library additions/updates
- deprecation of node10
bsky.app/profile/type...
TypeScript 6.0 introduces a new flag: --stableTypeOrdering
It's a migration-assist flag to allow comparison of *.d.ts files made by TS 6.0 vs the future TS 7.0 Go compiler ⚖️
TS 7.0 relies on consistent type sorting across the many parallel compiler threads 🧵
devblogs.microsoft.com/typescript/a...
It's a migration-assist flag to allow comparison of *.d.ts files made by TS 6.0 vs the future TS 7.0 Go compiler ⚖️
TS 7.0 relies on consistent type sorting across the many parallel compiler threads 🧵
devblogs.microsoft.com/typescript/a...
February 11, 2026 at 8:35 PM
TypeScript 6.0 introduces a new flag: --stableTypeOrdering
It's a migration-assist flag to allow comparison of *.d.ts files made by TS 6.0 vs the future TS 7.0 Go compiler ⚖️
TS 7.0 relies on consistent type sorting across the many parallel compiler threads 🧵
devblogs.microsoft.com/typescript/a...
It's a migration-assist flag to allow comparison of *.d.ts files made by TS 6.0 vs the future TS 7.0 Go compiler ⚖️
TS 7.0 relies on consistent type sorting across the many parallel compiler threads 🧵
devblogs.microsoft.com/typescript/a...
TypeScript 6.0 Beta is out 🎉
🔶 Temporal
🔶 Map#getOrInsert
🔶 RegExp.escape
🔶 #/ prefix for Package Imports
New defaults!
🔶 --target=ES2025
🔶 "use strict"
🔷 --strict
Deprecations!
🗑️ baseUrl, outFile
🗑️ import assertions
🗑️ `module` namespaces
🗑️ module: amd
🗑️ moduleResolution: node
🗑️ target: ES5
🔶 Temporal
🔶 Map#getOrInsert
🔶 RegExp.escape
🔶 #/ prefix for Package Imports
New defaults!
🔶 --target=ES2025
🔶 "use strict"
🔷 --strict
Deprecations!
🗑️ baseUrl, outFile
🗑️ import assertions
🗑️ `module` namespaces
🗑️ module: amd
🗑️ moduleResolution: node
🗑️ target: ES5
TypeScript 6.0 beta is now published!
This release brings
- inference improvements for functions
- updates to package.json 'imports'
- the Temporal APIs
- alignments for the upcoming TypeScript 7.0
- & more!
Try it today!
devblogs.microsoft.com/typescript/a...
This release brings
- inference improvements for functions
- updates to package.json 'imports'
- the Temporal APIs
- alignments for the upcoming TypeScript 7.0
- & more!
Try it today!
devblogs.microsoft.com/typescript/a...
Announcing TypeScript 6.0 Beta - TypeScript
Today we are announcing the beta release of TypeScript 6.0! To get started using the beta, you can get it through npm with the following command: npm install -D typescript@beta TypeScript 6.0 is a uni...
devblogs.microsoft.com
February 11, 2026 at 8:10 PM
TypeScript 6.0 Beta is out 🎉
🔶 Temporal
🔶 Map#getOrInsert
🔶 RegExp.escape
🔶 #/ prefix for Package Imports
New defaults!
🔶 --target=ES2025
🔶 "use strict"
🔷 --strict
Deprecations!
🗑️ baseUrl, outFile
🗑️ import assertions
🗑️ `module` namespaces
🗑️ module: amd
🗑️ moduleResolution: node
🗑️ target: ES5
🔶 Temporal
🔶 Map#getOrInsert
🔶 RegExp.escape
🔶 #/ prefix for Package Imports
New defaults!
🔶 --target=ES2025
🔶 "use strict"
🔷 --strict
Deprecations!
🗑️ baseUrl, outFile
🗑️ import assertions
🗑️ `module` namespaces
🗑️ module: amd
🗑️ moduleResolution: node
🗑️ target: ES5
Reposted by Rob Palmer
Our tsgo adoption at Vanta has been pretty high-impact. Everything is so, so much faster now.
February 11, 2026 at 5:12 PM
Our tsgo adoption at Vanta has been pretty high-impact. Everything is so, so much faster now.
Reposted by Rob Palmer
very excited for our first guest of the e18e & friends show to be @joshuakgoldberg.com!
He's done so many great things for open source already, so we're super happy to have him join us to chat about what he's been up to lately!
tune in tomorrow 🎉
He's done so many great things for open source already, so we're super happy to have him join us to chat about what he's been up to lately!
tune in tomorrow 🎉
February 9, 2026 at 10:35 AM
very excited for our first guest of the e18e & friends show to be @joshuakgoldberg.com!
He's done so many great things for open source already, so we're super happy to have him join us to chat about what he's been up to lately!
tune in tomorrow 🎉
He's done so many great things for open source already, so we're super happy to have him join us to chat about what he's been up to lately!
tune in tomorrow 🎉
Reposted by Rob Palmer
new release of the @e18e.dev github action 🚀
you can use this to diff changes in your dependencies. e.g. trust/provenance, duplicates, significant size increases, etc.
check it out!
you can use this to diff changes in your dependencies. e.g. trust/provenance, duplicates, significant size increases, etc.
check it out!
GitHub - e18e/action-dependency-diff: A GitHub action to report dependency changes and potential problems
A GitHub action to report dependency changes and potential problems - e18e/action-dependency-diff
github.com
February 8, 2026 at 1:35 PM
new release of the @e18e.dev github action 🚀
you can use this to diff changes in your dependencies. e.g. trust/provenance, duplicates, significant size increases, etc.
check it out!
you can use this to diff changes in your dependencies. e.g. trust/provenance, duplicates, significant size increases, etc.
check it out!
Reposted by Rob Palmer
you have probably heard that webassembly supports garbage collection. are you looking for an ahead-of-time compiler for wasm with gc? as it happens, i have written a little monograph on the topic wingolog.org/archives/202...
ahead-of-time wasm gc in wastrel — wingolog
wingolog: article: ahead-of-time wasm gc in wastrel
wingolog.org
February 6, 2026 at 3:49 PM
you have probably heard that webassembly supports garbage collection. are you looking for an ahead-of-time compiler for wasm with gc? as it happens, i have written a little monograph on the topic wingolog.org/archives/202...
Reposted by Rob Palmer
communities grow fueled by the value they create for themselves. npmx is useful to us, and that is enough to bind us together and take care of our website long term. we already won.
February 7, 2026 at 8:22 AM
communities grow fueled by the value they create for themselves. npmx is useful to us, and that is enough to bind us together and take care of our website long term. we already won.
TypeScript excitement 😉
Congrats to Lionel-Rowe on landing support for RegExp.escape in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
Congrats to Lionel-Rowe on landing support for RegExp.escape in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
Add types for `RegExp.escape` by lionel-rowe · Pull Request #62138 · microsoft/TypeScript
Closes #61321
Towards #61735
github.com
February 7, 2026 at 2:02 AM
TypeScript excitement 😉
Congrats to Lionel-Rowe on landing support for RegExp.escape in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
Congrats to Lionel-Rowe on landing support for RegExp.escape in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
TypeScript excitement 😉
Congrats to @moriken.dev on landing support for the ES2025 target in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
Congrats to @moriken.dev on landing support for the ES2025 target in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
Introduce ES2025 target & Add missing ScriptTargetFeatures by petamoriken · Pull Request #63046 · microsoft/TypeScript
Fixes #61735
This PR includes the addition of 2 type files:
es2025.regexp.d.ts
es2025.intl.d.ts
Related issues and (stalled) PRs
ES2025 RegExp.escape (es2025.regexp.d.ts)
Closes #61321
Closes #62...
github.com
February 7, 2026 at 1:53 AM
TypeScript excitement 😉
Congrats to @moriken.dev on landing support for the ES2025 target in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
Congrats to @moriken.dev on landing support for the ES2025 target in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
github.com/microsoft/Ty...
TypeScript excitement 😉
Congrats to Renegade334 on landing support for @tc39.es "Upsert" in upstream TypeScript. Heading for TS 6.0 Beta next week 🎉
let map = new Map();
map.getOrInsert(key, defaultVal);
It sets a default value on a map key with no overwriting.
github.com/microsoft/Ty...
Congrats to Renegade334 on landing support for @tc39.es "Upsert" in upstream TypeScript. Heading for TS 6.0 Beta next week 🎉
let map = new Map();
map.getOrInsert(key, defaultVal);
It sets a default value on a map key with no overwriting.
github.com/microsoft/Ty...
Add proposal-upsert methods to lib.esnext.collection by Renegade334 · Pull Request #62612 · microsoft/TypeScript
proposal-upsert is now stage 3, shipped in Safari 18.4, shipping in Firefox 144, and staging in Chromium.
github.com
February 7, 2026 at 1:44 AM
TypeScript excitement 😉
Congrats to Renegade334 on landing support for @tc39.es "Upsert" in upstream TypeScript. Heading for TS 6.0 Beta next week 🎉
let map = new Map();
map.getOrInsert(key, defaultVal);
It sets a default value on a map key with no overwriting.
github.com/microsoft/Ty...
Congrats to Renegade334 on landing support for @tc39.es "Upsert" in upstream TypeScript. Heading for TS 6.0 Beta next week 🎉
let map = new Map();
map.getOrInsert(key, defaultVal);
It sets a default value on a map key with no overwriting.
github.com/microsoft/Ty...
TypeScript excitement 😉
Congrats to Renegade334 on landing type declarations for @tc39.es Temporal - the new JS Date-Time API - in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
Temporal is available in Firefox & Chrome today.
github.com/microsoft/Ty...
Congrats to Renegade334 on landing type declarations for @tc39.es Temporal - the new JS Date-Time API - in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
Temporal is available in Firefox & Chrome today.
github.com/microsoft/Ty...
Add lib.esnext.temporal by Renegade334 · Pull Request #62628 · microsoft/TypeScript
Closes #60164.
No custom calendar support, as per the latest spec changes.
There are lots of places in the spec where property bags have "at least one of" constraints (eg. either month or...
github.com
February 7, 2026 at 1:30 AM
TypeScript excitement 😉
Congrats to Renegade334 on landing type declarations for @tc39.es Temporal - the new JS Date-Time API - in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
Temporal is available in Firefox & Chrome today.
github.com/microsoft/Ty...
Congrats to Renegade334 on landing type declarations for @tc39.es Temporal - the new JS Date-Time API - in upstream TypeScript 🎉
Heading for TS 6.0 Beta next week 👍
Temporal is available in Firefox & Chrome today.
github.com/microsoft/Ty...
Reposted by Rob Palmer
Started iteration on ESM support in the Node.js embedder API with new overloads that likely will be less prone to ABI breakages as more features are added..
github.com/nodejs/node/...
Initial support has released in 25.6.0
nodejs.org/en/blog/rele...
github.com/nodejs/node/...
Initial support has released in 25.6.0
nodejs.org/en/blog/rele...
src: initial support for ESM in embedder API by joyeecheung · Pull Request #61548 · nodejs/node
This patch extends LoadEnvironment to support loading ES modules, and adds the following new types:
enum class ModuleFormat : uint8_t {
kCommonJS,
kModule,
};
// Data for specifying an entry p...
github.com
February 6, 2026 at 6:40 PM
Started iteration on ESM support in the Node.js embedder API with new overloads that likely will be less prone to ABI breakages as more features are added..
github.com/nodejs/node/...
Initial support has released in 25.6.0
nodejs.org/en/blog/rele...
github.com/nodejs/node/...
Initial support has released in 25.6.0
nodejs.org/en/blog/rele...
Reposted by Rob Palmer
From Chrome 145 (on general release next week!), DevTools we will start to show so called "soft" navigations and "Soft LCP" in the Performance Panel traces.
These are for SPAs which don't do a full page load, but instead "fake it" by updating the current page and pushing a new history entry.
1/5 🧵
These are for SPAs which don't do a full page load, but instead "fake it" by updating the current page and pushing a new history entry.
1/5 🧵
February 4, 2026 at 9:41 AM
From Chrome 145 (on general release next week!), DevTools we will start to show so called "soft" navigations and "Soft LCP" in the Performance Panel traces.
These are for SPAs which don't do a full page load, but instead "fake it" by updating the current page and pushing a new history entry.
1/5 🧵
These are for SPAs which don't do a full page load, but instead "fake it" by updating the current page and pushing a new history entry.
1/5 🧵
Reposted by Rob Palmer
🚀 Lazy Barrel Optimization in Rolldown
Barrel files, files that re-export from other modules, are common in modern JavaScript projects but a nightmare for your build time.
Rolldown now has Lazy Barrel Optimization to fix this.
Here's how it works 🧵
Barrel files, files that re-export from other modules, are common in modern JavaScript projects but a nightmare for your build time.
Rolldown now has Lazy Barrel Optimization to fix this.
Here's how it works 🧵
February 3, 2026 at 4:40 PM
🚀 Lazy Barrel Optimization in Rolldown
Barrel files, files that re-export from other modules, are common in modern JavaScript projects but a nightmare for your build time.
Rolldown now has Lazy Barrel Optimization to fix this.
Here's how it works 🧵
Barrel files, files that re-export from other modules, are common in modern JavaScript projects but a nightmare for your build time.
Rolldown now has Lazy Barrel Optimization to fix this.
Here's how it works 🧵
Reposted by Rob Palmer
🔥 NEW BANTER: "Scaling Node.js with the Right Signals: ELU"
CPU utilization is lying to you.
Your auto-scaler adds pods while your actual bottleneck gets worse.
Luca and I explain why ELU is the metric you should be watching.
📅 Feb 4th
CPU utilization is lying to you.
Your auto-scaler adds pods while your actual bottleneck gets worse.
Luca and I explain why ELU is the metric you should be watching.
📅 Feb 4th
February 2, 2026 at 4:59 PM
🔥 NEW BANTER: "Scaling Node.js with the Right Signals: ELU"
CPU utilization is lying to you.
Your auto-scaler adds pods while your actual bottleneck gets worse.
Luca and I explain why ELU is the metric you should be watching.
📅 Feb 4th
CPU utilization is lying to you.
Your auto-scaler adds pods while your actual bottleneck gets worse.
Luca and I explain why ELU is the metric you should be watching.
📅 Feb 4th
