Reilly O'Donnell

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Senior Frontend Engineer - Sharing everything I know about React, React Native, TS, and building fast, scalable apps

RemoteJoined September 2021

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Reilly O'Donnell's blogs

Reilly's Blogblog.reilly.dev16 posts

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ROReilly O'Donnellblog.reilly.devAug 14, 2025 · 3 min read

perf overhead on context flattener?

Someone shared this image above. At first glance, I wasn’t sure about the perf implications — so let’s break it down from first principles :D Let’s deconstruct this monster Here’s the code: // Function to flatten React Context Providers. const flatte...

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ROReilly O'Donnellblog.reilly.devApr 2, 2025 · 12 min read

Diving into SSR with bun & react 19

Intro Hello it’s me from the future! I originally was going to go over file based routing but pivoted to going over important SSR concepts with React / how Bun makes it easy. It’s full of struggles with hydration (mismatches), React entry points, and...

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ROReilly O'Donnellblog.reilly.devFeb 15, 2025 · 2 min read

overview of cloudflare workers - part 1

history? Serverless is EVERYWHERE and for good reason: nearly infinite scalability, physically closer to users, and pay-for-what-you-use pricing. But not without tradeoffs — vendor lock-in, (potentially) higher costs, and the infamous cold-starts. cf...

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ROReilly O'Donnellblog.reilly.devMar 12, 2024 · 1 min read

Send iMessage to a loved one from the terminal!

mkdir ~/bin Now let's go to it: cd ~/bin and create a file text.sh #!/bin/bash MESSAGE=$1 # Replace with their number (be sure to include the +1) PHONE_NUMBER=+11234567 if [ "$#" -ne 1 ]; then echo "Usage: $0 MESSAGE" exit 1 fi osascript...

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ROReilly O'Donnellblog.reilly.devFeb 28, 2024 · 2 min read

Building Scalable WebSocket APIs with Socket.IO Syntax

Sockets can only transmit binary (text.) Imagine we have this data const message = {id: '123', name: 'Reilly', message: 'Hey'} Here's the problem: we want to send this data to the ui but we have hundreds of useEffects spread throughout the codebase....

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Reilly O'Donnell

About

Available for

Reilly O'Donnell's blogs

Recently published

perf overhead on context flattener?

Diving into SSR with bun & react 19

overview of cloudflare workers - part 1

Send iMessage to a loved one from the terminal!

Building Scalable WebSocket APIs with Socket.IO Syntax

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Reilly O'Donnell

About

Available for

Reilly O'Donnell's blogs

Recently published

perf overhead on context flattener?

Diving into SSR with bun & react 19

overview of cloudflare workers - part 1

Send iMessage to a loved one from the terminal!

Building Scalable WebSocket APIs with Socket.IO Syntax