Young Reacts #61 – Feature Flag Working Group

During my last compensation review, one identified growth area was to expand my impact outside my team and applications. So I started looking for cross-cutting problems, one of which was the lack of a user-based feature flagging solution.

But I couldn’t just go and build the system I wanted since none would buy into my solution. A unilateral decision doesn’t work at Netflix due to our culture of freedom and responsibility. Therefore, most of the cross-cutting problems are solved via working groups, a group of interested people who work together to define needs, recommend a solution, and, possibly, implement the solution.

So I kicked off a working group on feature flags last week. Even though I have seen firsthand how the groups worked together to transition our servers to containers, and to introduce GraphQL, this time is my first attempt at running a working group. It will be a challenging and teaching experience. But I will get through it.

Photo by Perry Grone on Unsplash

People ❤

Where to Start

This article gave me a perspective on how to identify cross-cutting problems. A sequel to this article, Technical Research and Preparation, also suggests a possible path forward.

The 3 Things Employees Really Want: Career, Community, Cause

Facebook surveyed what employees look for from their employers. The three values resonated with me as well. It was good to have my wants organized neatly like this.

Software Engineering 🌐


Swift, a language originally designed by Apple for its UI applications, is now expanding to server applications just as Javascript and Kotlin did. To help with the expansion, Apple announced a library to enable cryptography using Swift on Linux.

Adding special values to types in TypeScript

Once you get used to modeling your data using Typescript, your thinking will become much more precise. This guide comprehensively shows how to represent different kinds of values.

JavaScript Libraries Are Almost Never Updated Once Installed

If it ain’t broke, don’t fix it is taken by heart by many engineers. This statistic shows precisely that.

Business 💸

Introducing Rolling Venture Funds

AngelList created a financial innovation to reduce fund-raising frictions for VCs. Will the new VCs, enabled by the lower barrier to entry, be able to change the VC industry?

Young Reacts #60 – Starting a meetup

I used to organize a monthly meetup for startup managers when I was in Seoul. I loved meeting new people, getting to know how they approached their roles, and exchanging ideas in a safe environment. I enjoyed it every time and now miss it dearly. That is why I planned to organize a similar event this year.

So for the first time, I organized a small gathering with people managers in South Bay this week. The turnout wasn’t large (4 in total), but I felt that it was a good start. The group was small enough to have in-depth discussions. I learned how certain teams at Epic Games, Chan Zuckerberg Initiative, and LinkedIn are organized, and was nudged to read about inwards, outwards, and holistics. I am planning to turn this into a regular event now.

Photo by Ashkan Forouzani on Unsplash

People ❤

High Output Management for (Non-managing) Tech Leads

High Output Management remains to be my favorite business book. One key lesson from the book is that a manager’s output equals the output of the organization under their supervision or influence. I’ve been thinking that the same applies to other types of leaders, such as senior engineers or tech leads, just as this article says.

Data-gather first, manage up second.

I have been disappointed by many managers before for their seeming lack of interest in my development. But this article made me regret not having more candid conversations about their motivations and priorities.

Software Engineering 🌐

The Feed Algorithm

I remember my old days at a startup where we tweaked our feed algorithm just a tiny bit to improve our numbers. There wasn’t much science to it. We had a lot of magic numbers, which made me wonder if others did it much better., a developer community, has its code open-sourced, which shows how it generates feeds for its users.

Staggered Animations with CSS Custom Properties

I am still not used to CSS custom properties that their smart usages always amaze me. I would have never thought to use the custom properties to create staggered animations.

Business 💸

Quadratic Payments: A Primer

Whether money is speech or not, the current political systems suffer from elitism and, as a reaction, populism. Quadratic payment, where your nth vote costs you n, is an experiment to reflect people’s preferences more accurately.

Young Reacts #59 – Lab Days

I participated in a two-day Lab Days last week in LA for our colleagues in Animation Studio. The event was like hack days, but different in three aspects: first, we weren’t expected to work days and nights. Second, we didn’t come up with the ideas but were assigned to the projects which had eager stakeholders. Third, we were expected to present a usable product at the demo. (The organizers intentionally named it Lab Days, not Hack days to convey the different expectations)

The second and third differences put a lot of pressure on me. I couldn’t just call it a day because I knew how painful the problem was to the stakeholders. At the same time, the result has to be solid. After our demo, where my stakeholder jumped up and down, I was fried. I didn’t work longer than regular hours, but I was so intensely focused. I don’t believe I can do this every day, but it was fun to understand a problem, ideate a solution together, and create a working prototype in two days.

Photo by Hans Reniers on Unsplash

People ❤

Performing a Project Premortem

This Twitter thread about preventable problems prompted me to read more about premortems. I can now see that people are incentivized to chase after highly-visible projects since it is hard to prove that one is an unsung hero. Premortems look like an excellent way to detect and reward people who discover preventable problems and prevent them.

Software Engineering 

Introducing Yarn 2! 🧶

Yarn, one of the two most popular package managers, has received a major update. As the article describes, a lot has changed, including backward-incompatible features such as Plug’n’play and protocols. I am afraid these won’t work with the existing libraries on npm.

Playwright: Node library to automate Chromium, Firefox and WebKit with a single API

Microsoft announced an exciting evolution of Puppeteer named Playwright. Its APIs are more suitable for testing thanks to setTimeout-free automation, which is a crucial improvement.

Mirage JS: A client-side server to develop, test and prototype your JavaScript app

As UI developers, we are usually at the end of the dependency chain. We always wait for our requirements, designs, and APIs. So I welcome any tool that can remove that dependency. Mirage JS seems to be able to unblock us from backend dependencies and enable more iterations and experiments.


Building a more private web: A path towards making third party cookies obsolete

Cookies have been integral to track users’ activities across different websites and, thus, enabling advertisements to be more targeted. Google’s Chrome team announced Privacy Sandbox last August to make the technology less invasive. This first step will stop cookies from being sent everywhere.

And other things I read

Young Reacts #58

I joined a meeting this week where we discussed how to handle error states. And it was hands down the best meeting experience. The facilitator sent an agenda long before, took notes of discussions, spared plenty of time to create action items, and shared the summary of the meeting on the same day. It was a rare find even at Netflix. This meeting will be my standard going forward.

Photo by You X Ventures on Unsplash

People ❤

How to manage a program in a product-mode organization

Even in a transparent workplace like Netflix, achieving alignment across different teams is hard. The company and the orgs have a high-level strategy; but each team plans its roadmap autonomously, which often doesn’t consider interdependencies. This article suggests that cross-functional projects call for different organizing methods.

Software Engineering 

Code-wise, cloud-foolish

When I think about lock-ins, I often think about vendor lock-ins, such as AWS or JIRA. But my opensource tech stacks have lock-in effects as well (since I can’t easily change my code), and I should be mindful of it.

Copying data is wasteful, mutating data is dangerous

An enlightening thought that a function interface needs to be immutable, but the internal can use mutation for optimization.

A short Twitter Thread on Typescript type arguments

These couple of tweets explained so much about how Typescript’s type arguments work.


A handy library if you want to use hooks and error boundaries at the same time.


The ‘No Code’ Delusion

No Code is trending in the tech industry at the moment. Engineers are expensive, and products take too long to build. The article reacts to the movement. I liked the parallel between this generation of tools and the old drag-and-drop website editors, which failed to replace all UI engineers.

Young Reacts #57 – What Happens When Your Career Becomes Your Whole Identity

This article, What Happens When Your Career Becomes Your Whole Identity, caught my eyes this week. I’ve always valued work-life balance when I started working. While my professional achievements are significant to me, they never defined me. To some degree, the separation was easy because no one knew of the companies I worked for for the first seven years.

After I started working at Netflix, people who I meet for the first time know of me as a “Netflix engineer.” Who I am is less impressive to them than where I work. At first, I appreciated the new respect and interests my job has brought to me. But now I worry that this prestige would be too hard to let go, especially when I keep measuring myself against my peers and friends.

The article has several recommendations to battle this trapping; I found it most helpful to broaden my perspective to see my career in terms of not my company or title, but skills and greater goals. It will be hard to let go when the time comes. But I hope the article helps me in the future.

Photo by Hunters Race on Unsplash

Software Engineering 🌐

Write tests. Not too many. Mostly integration.

It is an interesting read because I haven’t seen many “real” unit tests in real life. Most teams I worked at chose not to mock/fake things out because of difficulty. But I agree with the premise that the unit tests are useful only in some instances.

What are the differences between the private keyword and private fields in TypeScript?

Private fields (fields that start with #) are part of Class fields proposal, which is at stage 3. This StackOverflow question helped to clarify the differences; the core is that private keywords check at compile-time and private fields check at runtime.

7.8.0 Released: ECMAScript 2020, .mjs configuration files and @babel/cli improvements

Now that null coalescing operators and optional chaining are at stage 4, Babel 7.8 support them by default.

The story of a V8 performance cliff in React · V8

A probably useless, still eye-opening article for UI engineers. I find leaking abstractions fascinating.

Business 💸

State of Startups 2019

This annual survey made me appreciate that startups don’t happen overnight. Looking at the age of the startups, most have been around for more than three years, but yet, most are not profitable.

Enforcing Against Manipulated Media

Facebook, while it won’t remove political ads, will delete manipulated/generated photos or videos (think deepfake). On a related note, a notable Facebook leader Andrew Bosworth posted thoughts on its role in the past and the coming elections.

Young Reacts #56 – Back to Work

This week starts a new year for me after a long relaxing vacation. I don’t remember anything I was working on before the holidays, but I will be fine. Looking forward to this exciting year 💪! (especially with the US election…)

Photo by William Iven on Unsplash

People ❤️

Career Growth Frameworks in Software Engineering: A Review

A long (20-min long!) summary of popular ideas on engineers’ career growth frameworks. Of all the ideas, the most important is that the cultural values and the growth framework should be aligned.

The one-salary experiment, ten years in

This company iwantmyname challenges the assumption that pay differences must exist for hiring and retention. Instead, they opted to pay everyone the same, regardless of role, experience, or cost of living and have done it for ten years now.

Words I Wish You’d Stop Using, system fonts only

In short, the term “minority” disregards the power struggle aspect of the label and dehumanizes those groups. Use “minoritized people” to acknowledge that people aren’t born minorities, but made into them.

Software Engineering 🌐

What does it mean for a machine to “understand”?

This article is about AI but applies to other fields as well. Defining a problem is often the hardest part of the complex problems. Creating codified and testable definitions will orient the discussions. Nothing is worse than the moving goalposts.

Act locally, connect globally with IoT and edge computing

Edge computing, or local computing under limited connectivity and bandwidth, will open up new use cases in the coming decade. Current use cases summarized by Amazon’s CTO.

Why We Don’t See Many Public GraphQL APIs

GraphQL’s flexibility is a challenge when the consumers are not familiar with the convention of the API since each provider can handle edge-cases (errors, timeouts, and so on) differently.

Young Reacts #54

Of all the benefits and perks from working at Netflix, I love meeting and learning from smart people with intriguing, diverse backgrounds the most. I had a chance to talk to an iOS engineer about my thesis that all platforms are doing the same architecture (currently component architecture with unidirectional data flow) with different lingos. As he had a game development background, he told me that that idea, especially unidirectional data flow, is an old idea (game loop) that originated from game development.

He also pointed out that since Apple and Google own mobile platforms, mobile developers tend to wait for those two to solve the architectures. But because no one entity controls the web, web developers try many different ideas like Angular 1’s MVC, React’s Components, or Flow Architecture.

I don’t often hear things that change my perspectives, but those two were definitely eye-opening. So I was very grateful after the discussion. Maybe for your new year resolution, try reaching out to people you don’t usually talk to more!

Photo by Priscilla Du Preez on Unsplash

People ❤️

Containers Will Not Fix Your Broken Culture (and Other Hard Truths)

This is an excellent article full of great quotes and links. The message is simple: no technology will change how people behave. I had the same message when I presented the progress on GraphQL adoption to my org.

Software Engineering 🌐

2019 State of JavaScript

It’s this time of the year again. Here are my takeaways: 1. GraphQL’s sustained popularity and interest. 2. Typescript’s sustained popularity and interest. 3. Svelte’s surprising amount of interest and awareness (75% awareness is high considering its short history).

Entities, components and systems

I heard about Entities Components Systems from the said conversation and looked it up. From my understanding, it is an architecture to optimize the memory access pattern to overcome slow memory speed relative to CPU speed. Not relevant to web development, but I still found it cool 😎

GraphQL Batching Attack

With new technology comes a new attack surface. GraphQL’s flexibility exposes a new attack surface that traditional prevention and monitoring tools (request based rate-limiting and telemetry) can’t handle well.

Business 💸

One year later, restaurants are still confused by Google Duplex

Remember the freaky, yet exciting Google Duplex announcement? My family finally got to try it yesterday, which got me to wonder if Duplex further adds more stress to the more vulnerable workers. This Verge profile, albeit a little dated, describes how the technology works in the real world.