Learn react source code and wow everyone

As a front-end engineer using React for many years, do we still use various application layer libraries and frameworks? Do we encounter some questions about react source code during the interview? Would you like to see the React underlying logic?

Why learn react source?

  1. Prerequisite to be a Senior or senior front-end engineer: As a front-end engineer, if you are not satisfied with the development of the application level, or want to become a senior or senior front-end engineer, it is necessary to be familiar with the ability. Why do you say that?reactAs a frequently used front-end library, reactivejsxThe statement,virtual-dom,diffThe algorithm,fiberScheduling,current-modeThe idea has become an effective idea to build front-end quick response page. Some will say, the underlying source daily development with less than I, indeed, if we can only meet the copy paste, or build a simple page, with some communities have some libraries, really don’t need, but we are a new generation of young people have ideal have ambition, and if you want to go further in his career, only in the use of level, our competitiveness will be discounted, It’s a skill we need to learn, even to improve our skills or raise our salary.
  2. Interview needs: now more than a year of front-end positions are beginning to require familiarity with a frequently used library, or the source of the framework, if you are daily developmentreactUse more words, that familiarreactSource code will certainly be a plus in your interview if you canreactThe operation mechanism of each module, and how they are combined with the work, plus some problems encountered in the process of development, and then through reading the source code have a new understanding, will certainly let the interviewer sit up and take notice.
  3. Need to improve daily development skills: while we don’t have direct access to source code in daily development, we can optimize the performance of components, debug some render bugs, or work with othersreactRelated upgrades, as well as its design ideas, these need to be understood or solved from the source level, like building a house, without a solid foundation or underlying logic, how can you build a superstructure.

React source code is difficult to learn?

Of course, it’s hard to learn. React has gone from version 15 to version 17, and will soon be released in version 18. It’s been a constant iteration. From stack Reconcile to current Mode for fast response, Scheduler(scheduling fiber), Lane(fine-grained task priorities), and on top of that batchedUpdates and Suspense, All of this has evolved toward building faster applications,

To get a feel for the difference between using asynchronous interruptible updates, see the following two images

If you try to open the React source code, you’ll find that there is a lot of code in it. If you read it one by one, you’ll lose all sense of what’s going on. If you open the Function call stack of the React application, you’ll get stuck in the call stack of various functions. Is this a head pain?

How to learn react source code?

Don’t be discouraged. There are ways to learn react. Although the source code is abundant and difficult to understand, if you study each module systematically, analyze why it is designed this way and what its purpose is, you will understand the original intention and efforts of the developers of React

  1. understandreactDesign concept: from the design concept, analysisreactIt’s a bit like finding a girlfriend. You first have to know what she likes, then know her past, and then follow throughreactWhy is it designed the way it is, contrastvueAnd other libraries for building pages. What are its advantages and limitations?
  2. Module learning: Have broken the digestion of knowledge, fat is a stammer out, encountered a difficult challenge, and can be resolved on it, to understand the logic of the framework, and then the effect on the function of each module and have a general understanding, then there is deep into the details of each module, like building a house, a route or way of thinking of learning, Will not fall into each module or function call relationship, the first time to read the source code to remember the implementation of each function, familiar with their functions and role, and then gnaws specific details, learning source code is not a matter of a day, need to repeatedly to figure outreactDeveloper’s intentions.
  3. Follow the call stack and sample debugging: try writing something smalldemo, along with the initial call function debugging each function, combined with the source code comments or refer to what I learned beforereactSource code analysis series article, each module one by one to break, such as seehookRelated source, can try to write a withuseStateComponent, lookmountandupdateThe time,hookHow do they mount and update, and how do they update in different modes, for examplelegacyandcurrentThe difference under the pattern, and so on familiarhookAfter the source code can also try a handwrittenhookandhookUnderstanding.
  4. Learn with questions: according to common interview questions, try to find answers in the source code, and finally answer these questions to your colleagues. On the one hand, output is the best learning, on the other hand, it is also an opportunity to communicate, often meet the questions can refer to the previous article 1. The opening paragraph introduces and questions

Video explanation (efficient learning) :Click on the learning

React source code

1. Introduction and questions

2. React design philosophy

React source code architecture

4. Source directory structure and debugging

5. JSX & core API

Legacy and Concurrent mode entry functions

7. Fiber architecture

8. Render phase

9. The diff algorithm

10. com MIT stage

11. Life cycle

12. Status update process

13. Hooks the source code

14. Handwritten hooks

15.scheduler&Lane

16. Concurrent mode

17.context

18 Event System

19. Write the React mini

20. Summary & Answers to interview questions in Chapter 1