Less Struggle With Lifetimes

Rate this content
Bookmark

How many times in your developer career you forget to remove an event listener? Close web socket connection? Unsubscribe from updates from any source? Or you are just to run some cleanup tasks, but every time you should do it manually. In this talk, I will show a new concept “Lifetime”, which will change your mindset about solving the problems above, make it all easy and even automated. I will show how I use it in everyday development and how it makes my application better and secure. I will also show how it improves DX and productivity. And I believe it’s something your team might want to use too.

Egor Ogarkov
Egor Ogarkov
6 min
02 Dec, 2022

Comments

Sign in or register to post your comment.

Video Summary and Transcription

The Talk introduces the concept of Lifetime in software development, which is used to handle clean-ups. By using a simple object called Lifetime, engineers can bind clean-up functions and reuse them throughout their applications. Lifetimes can be nested, allowing for the creation of chains and trees to manage dependencies. The Talk also mentions the ability to create different types of lifetimes, such as sequential lifetimes, which can be useful for canceling requests or cleaning up effects from previous iterations.

Available in Español

1. Introduction to Lifetime Concept

Short description:

Let's get started. Today I'm going to tell you about the Lifetime concept that we use in our applications. LiveTime is a live stream. We're going to show you the same thing, but live stream. This is a piece of code. We have to write all this boilerplate code again and again. But we are engineers and our job is to make manual routine automatic.

Thanks. Thank you. Let's get started. And now, please welcome Igor and Ned. Thank you for having me.

Okay. So, my name is Igor. I'm a software engineer at JetBrains. And today I'm going to tell you about the Lifetime simple, but powerful concept that we use in our applications.

So, to give you some background, I'll show you this piece of content for the slides. This is a slide that you see on the screen. And it's called LiveTime.

So, this is a live stream. So, this is live stream. So, it's an awesome live broadcast. And we're going to show you live stream. So, we're going to show you the same thing, but live stream. Not live stream, live stream. Live stream. Live stream.

So, this is a piece of code. I'm sure you're all familiar with them. And maybe you, as me, were annoyed sometimes and wondering why all of this don't clean up automatically. We have to write all this boilerplate code again and again. Every time we add an event listener or subscription or something similar.

And, yes. I know why we need to do this. We have to try to avoid memory leaks, bugs and sometimes even risk. I'm sure that you all don't want your app to work because something wasn't removed before. But we are engineers and our day-to-day job is to make manual routine to be automatic.

2. 'Lifetime' in Engineering

Short description:

In our application, Engineer Brains, we use a simple object called Lifetime to handle clean-ups. You write a wrapper around an API, bind the clean-up to Lifetime, and then reuse it everywhere. By calling terminate, all your cleanup functions will be called. Lifetime helps you make your code logic more scalable and you can even create your own different types of lifetimes. For example, you can create sequential lifetimes that terminate the current one when you create the next lifetime. This can be useful in situations where you want to cancel previous requests or clean up effects from previous iterations.

All that I've showed you can be handled by something. In our application, Engineer Brains, we call this something Lifetime. What is Lifetime? In a nutshell, it's just a simple object to which we delegate doing all the clean-ups. So, as you can see, it has two steps, is it terminated or not. And you can always add any number of functions which will be called after termination.

It looks very simple and here it is, how we use it. Basically, you need to write a wrapper around some API like event listener, subscription, etc. and bind the clean-up to Lifetime. And yes, you still have to write your clean-up code, but you see, you do it only once. And then you just reuse it everywhere. Just the same for you as writing the React component. Still looks very easy, yes. Then you just use this function, pass Lifetime there, and that's it.

But the major point here, as you can see, you still have control outside in one place. So you decide when to terminate all of this at once, and you don't need to define the clean-up logic in some other places because you have it here. And just like it, all your boilerplate code is now replaced by one line. Just call terminate and all your cleanup functions will be called. So you don't need to think about when something will be dropped, it was automatically done for you. And as I said, you can call your lifetime termination whenever it's needed. So like here you can bind termination or unmount. It's very basic and I'm sure it's very useful for most of you. And because of the simplicity, you can compose it with almost everything. So having all the lifetime logic in one place helps you to make your code logic more scalable. So you can even extend and create your own different types of lifetimes. Now I can just show you a couple of advanced examples of it. So here you can create sequential lifetimes, which terminates the current one. When you create the next lifetime. Like here in this example on the right from me, every time you call next the new lifetime is returned and the previous is destroyed. It could be useful in a situation when you fire the same request multiple times but you want the previous one to be canceled. For example, you can also use it in a user failure because on every effect you might run new effects, but clean up everything from the previous iteration.

3. Nested Lifetimes and Examples

Short description:

Here, you can create nested lifetimes, which allows you to build lifetime chains and trees. This powerful feature lets you represent your entire application as a lifetime tree, declaratively managing dependencies. When a lifetime is terminated, all its nested lifetimes are destroyed. Check out more examples on our GitHub repo and code library, and don't forget to visit our JetPrints product called Space. If you want some JetPrints stickers, I might still have one.

Here you can create nested lifetimes. For me, it's the most powerful thing because you can create these lifetime chains or even lifetime trees. You can even represent the whole application as such a lifetime tree and put all the dependencies declaratively. You don't need to worry about terminating them all at once. If a lifetime at any level is terminated, all its nested, and then nested, and then nested are destroyed too.

And that's actually it. That's all with the examples. More of them you can find on the GitHub repo as well as the code library and some wrappers. There is a link on the screen. And there is also a link to our JetPrints product called Space where I work. And also if you want to grab some JetPrints stickers, I think I still have one.

And that's it.

Check out more articles and videos

We constantly think of articles and videos that might spark Git people interest / skill us up or help building a stellar career

A Guide to React Rendering Behavior
React Advanced Conference 2022React Advanced Conference 2022
25 min
A Guide to React Rendering Behavior
Top Content
React is a library for "rendering" UI from components, but many users find themselves confused about how React rendering actually works. What do terms like "rendering", "reconciliation", "Fibers", and "committing" actually mean? When do renders happen? How does Context affect rendering, and how do libraries like Redux cause updates? In this talk, we'll clear up the confusion and provide a solid foundation for understanding when, why, and how React renders. We'll look at: - What "rendering" actually is - How React queues renders and the standard rendering behavior - How keys and component types are used in rendering - Techniques for optimizing render performance - How context usage affects rendering behavior| - How external libraries tie into React rendering
Building Better Websites with Remix
React Summit Remote Edition 2021React Summit Remote Edition 2021
33 min
Building Better Websites with Remix
Top Content
Remix is a new web framework from the creators of React Router that helps you build better, faster websites through a solid understanding of web fundamentals. Remix takes care of the heavy lifting like server rendering, code splitting, prefetching, and navigation and leaves you with the fun part: building something awesome!
React Compiler - Understanding Idiomatic React (React Forget)
React Advanced Conference 2023React Advanced Conference 2023
33 min
React Compiler - Understanding Idiomatic React (React Forget)
Top Content
React provides a contract to developers- uphold certain rules, and React can efficiently and correctly update the UI. In this talk we'll explore these rules in depth, understanding the reasoning behind them and how they unlock new directions such as automatic memoization. 
Using useEffect Effectively
React Advanced Conference 2022React Advanced Conference 2022
30 min
Using useEffect Effectively
Top Content
Can useEffect affect your codebase negatively? From fetching data to fighting with imperative APIs, side effects are one of the biggest sources of frustration in web app development. And let’s be honest, putting everything in useEffect hooks doesn’t help much. In this talk, we'll demystify the useEffect hook and get a better understanding of when (and when not) to use it, as well as discover how declarative effects can make effect management more maintainable in even the most complex React apps.
Routing in React 18 and Beyond
React Summit 2022React Summit 2022
20 min
Routing in React 18 and Beyond
Top Content
Concurrent React and Server Components are changing the way we think about routing, rendering, and fetching in web applications. Next.js recently shared part of its vision to help developers adopt these new React features and take advantage of the benefits they unlock.In this talk, we’ll explore the past, present and future of routing in front-end applications and discuss how new features in React and Next.js can help us architect more performant and feature-rich applications.
(Easier) Interactive Data Visualization in React
React Advanced Conference 2021React Advanced Conference 2021
27 min
(Easier) Interactive Data Visualization in React
Top Content
If you’re building a dashboard, analytics platform, or any web app where you need to give your users insight into their data, you need beautiful, custom, interactive data visualizations in your React app. But building visualizations hand with a low-level library like D3 can be a huge headache, involving lots of wheel-reinventing. In this talk, we’ll see how data viz development can get so much easier thanks to tools like Plot, a high-level dataviz library for quick & easy charting, and Observable, a reactive dataviz prototyping environment, both from the creator of D3. Through live coding examples we’ll explore how React refs let us delegate DOM manipulation for our data visualizations, and how Observable’s embedding functionality lets us easily repurpose community-built visualizations for our own data & use cases. By the end of this talk we’ll know how to get a beautiful, customized, interactive data visualization into our apps with a fraction of the time & effort!

Workshops on related topic

React Performance Debugging Masterclass
React Summit 2023React Summit 2023
170 min
React Performance Debugging Masterclass
Top Content
Featured WorkshopFree
Ivan Akulov
Ivan Akulov
Ivan’s first attempts at performance debugging were chaotic. He would see a slow interaction, try a random optimization, see that it didn't help, and keep trying other optimizations until he found the right one (or gave up).
Back then, Ivan didn’t know how to use performance devtools well. He would do a recording in Chrome DevTools or React Profiler, poke around it, try clicking random things, and then close it in frustration a few minutes later. Now, Ivan knows exactly where and what to look for. And in this workshop, Ivan will teach you that too.
Here’s how this is going to work. We’ll take a slow app → debug it (using tools like Chrome DevTools, React Profiler, and why-did-you-render) → pinpoint the bottleneck → and then repeat, several times more. We won’t talk about the solutions (in 90% of the cases, it’s just the ol’ regular useMemo() or memo()). But we’ll talk about everything that comes before – and learn how to analyze any React performance problem, step by step.
(Note: This workshop is best suited for engineers who are already familiar with how useMemo() and memo() work – but want to get better at using the performance tools around React. Also, we’ll be covering interaction performance, not load speed, so you won’t hear a word about Lighthouse 🤐)
Concurrent Rendering Adventures in React 18
React Advanced Conference 2021React Advanced Conference 2021
132 min
Concurrent Rendering Adventures in React 18
Top Content
Featured WorkshopFree
Maurice de Beijer
Maurice de Beijer
With the release of React 18 we finally get the long awaited concurrent rendering. But how is that going to affect your application? What are the benefits of concurrent rendering in React? What do you need to do to switch to concurrent rendering when you upgrade to React 18? And what if you don’t want or can’t use concurrent rendering yet?

There are some behavior changes you need to be aware of! In this workshop we will cover all of those subjects and more.

Join me with your laptop in this interactive workshop. You will see how easy it is to switch to concurrent rendering in your React application. You will learn all about concurrent rendering, SuspenseList, the startTransition API and more.
React Hooks Tips Only the Pros Know
React Summit Remote Edition 2021React Summit Remote Edition 2021
177 min
React Hooks Tips Only the Pros Know
Top Content
Featured Workshop
Maurice de Beijer
Maurice de Beijer
The addition of the hooks API to React was quite a major change. Before hooks most components had to be class based. Now, with hooks, these are often much simpler functional components. Hooks can be really simple to use. Almost deceptively simple. Because there are still plenty of ways you can mess up with hooks. And it often turns out there are many ways where you can improve your components a better understanding of how each React hook can be used.You will learn all about the pros and cons of the various hooks. You will learn when to use useState() versus useReducer(). We will look at using useContext() efficiently. You will see when to use useLayoutEffect() and when useEffect() is better.
React, TypeScript, and TDD
React Advanced Conference 2021React Advanced Conference 2021
174 min
React, TypeScript, and TDD
Top Content
Featured WorkshopFree
Paul Everitt
Paul Everitt
ReactJS is wildly popular and thus wildly supported. TypeScript is increasingly popular, and thus increasingly supported.

The two together? Not as much. Given that they both change quickly, it's hard to find accurate learning materials.

React+TypeScript, with JetBrains IDEs? That three-part combination is the topic of this series. We'll show a little about a lot. Meaning, the key steps to getting productive, in the IDE, for React projects using TypeScript. Along the way we'll show test-driven development and emphasize tips-and-tricks in the IDE.
Web3 Workshop - Building Your First Dapp
React Advanced Conference 2021React Advanced Conference 2021
145 min
Web3 Workshop - Building Your First Dapp
Top Content
Featured WorkshopFree
Nader Dabit
Nader Dabit
In this workshop, you'll learn how to build your first full stack dapp on the Ethereum blockchain, reading and writing data to the network, and connecting a front end application to the contract you've deployed. By the end of the workshop, you'll understand how to set up a full stack development environment, run a local node, and interact with any smart contract using React, HardHat, and Ethers.js.
Designing Effective Tests With React Testing Library
React Summit 2023React Summit 2023
151 min
Designing Effective Tests With React Testing Library
Top Content
Featured Workshop
Josh Justice
Josh Justice
React Testing Library is a great framework for React component tests because there are a lot of questions it answers for you, so you don’t need to worry about those questions. But that doesn’t mean testing is easy. There are still a lot of questions you have to figure out for yourself: How many component tests should you write vs end-to-end tests or lower-level unit tests? How can you test a certain line of code that is tricky to test? And what in the world are you supposed to do about that persistent act() warning?
In this three-hour workshop we’ll introduce React Testing Library along with a mental model for how to think about designing your component tests. This mental model will help you see how to test each bit of logic, whether or not to mock dependencies, and will help improve the design of your components. You’ll walk away with the tools, techniques, and principles you need to implement low-cost, high-value component tests.
Table of contents- The different kinds of React application tests, and where component tests fit in- A mental model for thinking about the inputs and outputs of the components you test- Options for selecting DOM elements to verify and interact with them- The value of mocks and why they shouldn’t be avoided- The challenges with asynchrony in RTL tests and how to handle them
Prerequisites- Familiarity with building applications with React- Basic experience writing automated tests with Jest or another unit testing framework- You do not need any experience with React Testing Library- Machine setup: Node LTS, Yarn