Frontend engineering articles on JavaScript, React, TypeScript and more by Romain Trotard.https://www.romaintrotard.com/https://www.romaintrotard.com/posts/debugging-node-process/https://www.romaintrotard.com/posts/debugging-node-process/`console.log` works for simple debugging, but when things get complex, the `Node.js` **inspect mode** is your best friend. Let’s see how to attach your devtools and debug your processes like a pro.Sun, 15 Feb 2026 00:00:00 GMThttps://www.romaintrotard.com/posts/sentry-third-party-filter-exploration/https://www.romaintrotard.com/posts/sentry-third-party-filter-exploration/Discover how Sentry's thirdPartyErrorFilterIntegration enhances error monitoring by filtering and enriching stack traces. Learn about the setup, runtime processes, and how it ensures precise error reporting for your applications.Sun, 13 Jul 2025 00:00:00 GMThttps://www.romaintrotard.com/posts/sentry-exploration/https://www.romaintrotard.com/posts/sentry-exploration/Explore 2 issues causing your Sentry alerts to stop working in your React applications. Based on a real case, learn how I troubleshooted and resolved these problems to ensure your error monitoring stays effective.Wed, 10 Jul 2024 00:00:00 GMThttps://www.romaintrotard.com/posts/exploring-core-js-polyfication/https://www.romaintrotard.com/posts/exploring-core-js-polyfication/Polyfication is at the heart of ensuring seamless compatibility of JavaScript code across environments. Under the hood, core-js dynamically determines which polyfills are needed to augment features not supported by browsers. This behind-the-scenes magic allows developers to write modern JavaScript code with confidence, knowing that it will perform consistently across platforms.Tue, 14 May 2024 00:00:00 GMThttps://www.romaintrotard.com/posts/tanstack-router-typescript-wizardry/https://www.romaintrotard.com/posts/tanstack-router-typescript-wizardry/Explore how @tanstack/router transforms web development with its full type-safe approach. Learn about its innovative use of interfaces and 'declare module', ensuring a perfectly tailored routing experience based on your project's configuration.Sat, 20 Jan 2024 00:00:00 GMThttps://www.romaintrotard.com/posts/typesafety-mastering/https://www.romaintrotard.com/posts/typesafety-mastering/When you build a library, you want your code to be fully type safe and provide to developers the best experience possible. Unfortunately, sometimes it can be tricky to provide this full type safety. Let's see a tip to do it with an example.Tue, 05 Dec 2023 00:00:00 GMThttps://www.romaintrotard.com/posts/comparison-component/https://www.romaintrotard.com/posts/comparison-component/This component simplifies comparisons across different scenarios, allowing for easy highlighting of distinctions. You'll master its implementation effortlessly by the end of this article.Tue, 31 Oct 2023 00:00:00 GMThttps://www.romaintrotard.com/posts/serverless-function-cold-start-is-too-slow-lets-dockerize-our-app/https://www.romaintrotard.com/posts/serverless-function-cold-start-is-too-slow-lets-dockerize-our-app/In an application I built, I couldn't use edge function. Unfortunately, serverless function are so slow to start that I decided to dockerize my application and deploy it on my server.Wed, 28 Jun 2023 00:00:00 GMThttps://www.romaintrotard.com/posts/react-routing-library-with-navigation-api/https://www.romaintrotard.com/posts/react-routing-library-with-navigation-api/It's now time to connect the agnostic routing library that uses the navigation API to React.Wed, 05 Apr 2023 00:00:00 GMThttps://www.romaintrotard.com/posts/master-the-art-of-navigation-building-a-library-with-the-navigation-api/https://www.romaintrotard.com/posts/master-the-art-of-navigation-building-a-library-with-the-navigation-api/Now that we know what is the navigation API. Let's build a routing library agnostic of every framework.Wed, 08 Feb 2023 00:00:00 GMThttps://www.romaintrotard.com/posts/back-to-the-future-navigation-api/https://www.romaintrotard.com/posts/back-to-the-future-navigation-api/The new navigation API is coming. Ryan Florence said in a github issue that it will help to a better implementation for `react-router`. Let's explore this new API.Mon, 19 Dec 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/react-hook-form-unique-implem/https://www.romaintrotard.com/posts/react-hook-form-unique-implem/Forms are used everyday. Some library exists to improve both user and developer experience. `react-hook-form` is one of this library focusing on performance. Let's deep dive to this library.Wed, 16 Nov 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/js-cli-demystified/https://www.romaintrotard.com/posts/js-cli-demystified/I'm sure you use javascript CLI every day. For example, when using `eslint`, `prettier`, ... But do you know how to make your own js CLI and how it works?Tue, 26 Jul 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/exit-animation-with-framer-motion-demystified/https://www.romaintrotard.com/posts/exit-animation-with-framer-motion-demystified/Animation has their own implementation to deal with exit animation, because React do no allow to delay the unmounting of components. The `framer-motion` API seems to me to be the most natural one. Let's see the amazing implementation of exit animation with this library.Wed, 29 Jun 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/virtualization-with-fixed-size-items-part-1/https://www.romaintrotard.com/posts/virtualization-with-fixed-size-items-part-1/Have you performance issues because you have too many items in a list on your page? Let's see how to fix that thanks to virtualization.Wed, 01 Jun 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/useevent-the-new-upcoming-hook/https://www.romaintrotard.com/posts/useevent-the-new-upcoming-hook/Did you often transform React state to React ref not to re-create a new reference of your listener which is wrapped with useCallback because passed to a memo component. It happens to me so often, a new rfc for a new hook named useEvent has been opened by React that should make you happy :)Wed, 11 May 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/proxy-in-js-what-the-hell/https://www.romaintrotard.com/posts/proxy-in-js-what-the-hell/I am sure you are confident with object. But do you know that you can proxify them to intercept when a property is called to execute some custom code. Let's see what it is? How to use it? And some libraries that use it.Wed, 20 Apr 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/useimperativehandle-the-most-unknown-react-hook/https://www.romaintrotard.com/posts/useimperativehandle-the-most-unknown-react-hook/Now that React ref has no secret for you, we can look at the useImperativeHandle hook that allows us to expose functions to its parent thanks to its reference and inverse the unidirectional data flow.Wed, 06 Apr 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/things-you-need-to-know-about-react-ref/https://www.romaintrotard.com/posts/things-you-need-to-know-about-react-ref/React states are often overused because React refs are misunderstood. You will see what they are and when to use them. Do not use state when it's not useful anymore.Wed, 09 Mar 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/things-you-need-to-know-about-react-state/https://www.romaintrotard.com/posts/things-you-need-to-know-about-react-state/You probably used to use state, but do you know that you can lazy init it, update state with a callback, ... You will see from the fundamentals to more advanced things.Wed, 23 Feb 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/preventdefault-vs-stoppropagation/https://www.romaintrotard.com/posts/preventdefault-vs-stoppropagation/Do you always use `preventDefault` and `stopPropagation` because you don't know the difference? Let's see what is the role of each one.Wed, 09 Feb 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/when-to-use-usecallback/https://www.romaintrotard.com/posts/when-to-use-usecallback/Are you wondering when to use `useCallback`? I propose you my vision about it. And of course how it's implemented :)Wed, 26 Jan 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/unknown-console-api-in-js/https://www.romaintrotard.com/posts/unknown-console-api-in-js/If you only use `console.log`, do you know the other console methods which can make better logging? Let's see them.Wed, 12 Jan 2022 00:00:00 GMThttps://www.romaintrotard.com/posts/use-context-selector-demystified/https://www.romaintrotard.com/posts/use-context-selector-demystified/In the React context performance I talked about the `use-context-selector`, but how does it work under the hood?Wed, 29 Dec 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/css-clip-path-what-the-heck/https://www.romaintrotard.com/posts/css-clip-path-what-the-heck/Sometimes, you would like to store some data in the browser. Here is the Web Storage API that can make you happy. But what is it? And how to use it?Wed, 22 Dec 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/lets-explore-the-web-storage-api-localstorage-and-sessionstorage/https://www.romaintrotard.com/posts/lets-explore-the-web-storage-api-localstorage-and-sessionstorage/Sometimes, you would like to store some data in the browser. Here is the Web Storage API that can make you happy. But what is it? And how to use it?Wed, 24 Nov 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/react-context-performance/https://www.romaintrotard.com/posts/react-context-performance/React context is used by many libraries such as `react-router`, `react-query`, ... But what is it? How do we use it? What about the performances?Wed, 10 Nov 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/js-symbol-what-the-heck-hak/https://www.romaintrotard.com/posts/js-symbol-what-the-heck-hak/Symbol in javascript is something that is not well known but is still used without us knowing it. Let's take a look at it.Wed, 27 Oct 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/var-let-const-what-s-the-difference/https://www.romaintrotard.com/posts/var-let-const-what-s-the-difference/Daily, you probably use `var`, `let` or/and `const`, but do you know the differences between them? It's the subject of this article.Wed, 06 Oct 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/react-router-v6-demystified-part-3/https://www.romaintrotard.com/posts/react-router-v6-demystified-part-3/In this last article, we continue the exploration of the `react-router` code and our implementation.Wed, 22 Sep 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/react-router-v6-demystified-part-2/https://www.romaintrotard.com/posts/react-router-v6-demystified-part-2/In this second article, we will focus on understanding how is implemented `react-router` v6, and make a simpler implementation.Wed, 01 Sep 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/react-router-v6-demystified-part-1/https://www.romaintrotard.com/posts/react-router-v6-demystified-part-1/In this first article, we are going to see the main differences in the API of `react-router` v6 compared to the previous version.Tue, 17 Aug 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/explore-javascript-location-and-history-api/https://www.romaintrotard.com/posts/explore-javascript-location-and-history-api/The goal is to understand how works the Location and History API to implement a `react-router` library like.Wed, 04 Aug 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/animation-in-native-javascript/https://www.romaintrotard.com/posts/animation-in-native-javascript/If you wonder how to do some animations in javascript, it was the same for me. In this article, I present you what I discovered.Wed, 14 Jul 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/how-to-manage-internationalization/https://www.romaintrotard.com/posts/how-to-manage-internationalization/Let's explore how to implement internationalization with React to make your application understandable by everybody.Wed, 30 Jun 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/react-event-listeners-demystified/https://www.romaintrotard.com/posts/react-event-listeners-demystified/Let's go deep in the React implementation to know event listeners are handled.Sat, 12 Jun 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/debounce-throttle/https://www.romaintrotard.com/posts/debounce-throttle/In this article, we are going together how to use the functions throttle and debounce and how to implement them.Tue, 09 Feb 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/prevent-react-rerendering/https://www.romaintrotard.com/posts/prevent-react-rerendering/It can happen that performances are degraded. One of the possible reason can be that you have useless re-render. We are gonna focus, in this article, to see how to prevent useless re-render.Thu, 21 Jan 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/reselect-under-the-hood/https://www.romaintrotard.com/posts/reselect-under-the-hood/Let's look closely the code of the library Reselect, which handle memoization of Redux (and others) selectors.Mon, 04 Jan 2021 00:00:00 GMThttps://www.romaintrotard.com/posts/function-result-memoization/https://www.romaintrotard.com/posts/function-result-memoization/In this article, we are gonna explore how to do memoization in javascript.Tue, 22 Dec 2020 00:00:00 GMThttps://www.romaintrotard.com/posts/javascript-equalities/https://www.romaintrotard.com/posts/javascript-equalities/It exists different types of equality which are used in different cases. Let's explore them together.Sat, 19 Dec 2020 00:00:00 GMThttps://www.romaintrotard.com/posts/redux-under-the-hood/https://www.romaintrotard.com/posts/redux-under-the-hood/Let's explore together in this article, the well known library Redux, to see its implementationSat, 28 Nov 2020 00:00:00 GMT