React State Management - Intermediate JavaScript Course

React State Management is half of your React app so it is important for React developers to understand. In this full intermediate React tutorial, you will learn how to implement state management using industry best practices.
✏️ Jack Herrington created this course. He is a principal full stack engineer. Check out his channel: / @jherr
💻 Code!: github.com/jherr/fcc-state
⌨️ (0:00:00) Introduction
⌨️ (0:03:27) useState
⌨️ (0:18:37) useReducer
⌨️ (0:32:29) useMemo & useCallback
⌨️ (0:49:43) useEffect
⌨️ (1:05:59) useRef
⌨️ (1:13:53) Context and Custom Hooks
⌨️ (1:41:48) React Query & React Location
⌨️ (1:57:26) Zustand
⌨️ (2:06:11) Valtio
⌨️ (2:12:44) Jotai
⌨️ (2:20:51) Redux
⌨️ (2:37:56) The new use hook
⌨️ (2:44:26) Recommendations
⌨️ (2:46:07) Outroduction
🎉 Thanks to our Champion and Sponsor supporters:
👾 Nattira Maneerat
👾 Heather Wcislo
👾 Serhiy Kalinets
👾 Erdeniz Unvan
👾 Justin Hual
👾 Agustín Kussrow
👾 Otis Morgan
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[@Hizbullla]

Despite React's popularity it's so hard to find proper intermediate to advanced explanations about the nuances of the library. Seems like most React developers just copy paste and adjust code until they get the desired outcome. It's for this reason that I love Jack for his contribution to the tutorial landscape.

[@Castro_Gabriel]

I feel the same way.

[@vonderklaas]

You are right, Jack, Theo & some other dudes help with more advanced / senior things, rather than typical todo lists and stuff

[@technical3199]

yeah same here lol

[@mosesmolepo1702]

I'm guilty

[@Farouk-Dev]

Samee ❤

[@renielrabie9035]

I don’t think I’ve ever commented on a KZbin video, but Jack Herrington is one of the best teachers I’ve seen on the channel. Thank you, Jack. Thank you for a fun time learning state in React!

[@melkenhoning158]

This instructor is really skilled at explaining in just enough detail, good choice!

[@andreainvernizzi8510]

I learnt more about useState in 20 mins explained here than in a whole term of web development diploma from conventional education. I am so thankful to value-oriented YT channels like this one, are free sources of knowledge and value to everyone at the cost of an internet connection. Thank you for delivering this content about React

[@lukas.webdev]

I just posted a video about the same topic (in 2023) - maybe this could be interesting for you as well. 😉

[@marvinfok65]

Agreed! I no longer want to learn from conventional education! They set a time frame and just throw everything to you and expect you to know and they considered their job done!

[@Eyezbergslim]

This was one of the most comprehensive tutorials I've watched,. I really like how you gave examples of why the state doesn't change when discussing useState.

[@tomarapetty]

This is a really great mini course. Loved it! I went and followed Jack's channel as well! Thanks for putting this together.

[@nikolakikanovic9740]

Jack is actually one of few rare guys that covers and teaches you intermediate topics about react/next and typescript on his channel. One thing that I also like for him is that he with all that knowledge, you hear from the voice that he is still on to ground without any ego-trips, he is there to only teach you and transfer a knowledge. Good job Sensei!

[@jherr]

Thank you!

[@thebattinson1278]

I agree !

[@therealdevopsintern]

@@thebattinson1278 true

[@Eddie4k]

This is seriously such a great instructor!

[@EndiOdobasic]

wow, this is actually super important and it was so hard to actually find something that covers these concepts so well. thank you!

[@studyingasyouwere]

I learnt HTML and CSS from your channel from scratch and now I am posting my own web dev content! Thank you for your work :)

[@germanguerci1744]

This is the most important video about React I have ever seen in over 3 years of using React. Thank you!

[@Crevulus]

This man is the reason I went from junior to medior. You seriously must watch his videos if you're serious about a career with React.

[@tjdgmlchl6305]

Best tutorial. This is so helpful. Words cannot explain how grateful I am to have access to invaluable educational material like this.

[@usmanmalik-xk5vi]

Awesome resource man, Thank you for not just explaining how state management works but how the underlying data structure is handled by JS for example by reference and by value.

[@r-i-ch]

Jack is maybe the best intermediate content creator. Glad to see him here!

[@hhao0011]

easily the best react video and the best teacher. thank you for doing this !

[@mks5988]

your always great ,right time providing right course for the subscriber .thanks for the educator

[@AmirRazavi98]

Jack, You are AWESOME!!!! I think this tutorial was by far better than other react and state management's videos I've seen so far. Thanks for sharing your incredible knowledge.

[@lukas.webdev]

I just posted a video about the same topic (in 2023) - maybe this could be interesting for you as well. 😉

[@jigneshpatel8975]

It's Incredible! Got the actual understanding of state management from this. Kudos to Jack!

[@arghyasaha7259]

Thank you sir. Your useEffect video was very informative. i learned the why along with the how

[@stavroskefaleas6320]

Awesome tutorial. The only thing missing of the useState video is the classic example with 3 consecutive setCount functions that add 1 but the user get 1 again as a result. Then you teach about previous state!

[@thwackspongbelm]

Highly instructive, thank you. 18 minutes in, I can't wait to watch the rest

[@user-oz7eu7ps9r]

I have been learning react since months but this video just hit different! Jack is so amazing! Only after watching this video did I truly understood stage management!

[@federicamariani3294]

Jack is a monument and I'm so glad to see him here on FCC ❤

[@umair.ramzan]

Thanks for this, it's really worth the time I have put into it.

[@prasad_yt]

Great refresher , Yet learnt some new things.

[@gogaimerlishvili4542]

Thank you very much for this course, I think you explain the best among the lecturers.

[@eleah2665]

Jack is great. Do whatever he tells you to do. You will thank him later.

[@eliuddyn]

Jack is the best talking about React and Next 🔥🔥

[@bikerd12]

Fantastic tutorial!! Thank you.

[@codematics8344]

this is really well explained. thank you

[@andreiKspb]

Best of the Best, ty Mr.Herrington a lot. You are really awesome

[@AurelianoShowsTheWorld]

Thank you, that's a very nice video!

[@ChristopherBrown-bj4zl]

Alright... 7 minutes in and I can already tell this is a good video. So many "tutorials" gloss over the nuances of lines of code and this tutorial doesn't. This tutorial also goes a step further by showing code that you would think would work, but actually doesn't and explains why. For me, I need this. I need to know why something is happening, because under-the-hood/behind-the-scenes magic never works for me in the long run.

[@totallypointlessvideos3832]

This is really and awesome video. Many thanks for this!

[@santanu29]

Next make a Advanced React course. it will help me greatly in my job. Thank you for all the awesome content.

[@Poohbify]

I'm interested to know how to create this with TypeScript. Excellent tutorial. I will spend the next couple of days to build alongside.

[@martinsolheim6202]

Loved the squirrel raiding the bird feeder in the start of the video 😂

[@omarlaralima2459]

Hello Jack. Thank you for your time and effort to help improve our skills. Question: I have modified your code slightly where I am importing an array of names instead of hard coding it in the components. I am running into a slight problem where I cannot add a coma and space between the names from the array. how can I add this minor detail? Thank you for your time!

[@developerpranav]

This might be the last state management video one needs to watch for a long time, until they hit any limitations (which I dont think they will for a long time!)

[@krobi26]

I've been using React for about a year and a half, but I think I got 50% better at React by just watching this course.

[@snoussihamza2345]

A master piece!! The vscode configurations is from another planet 🤯 Can you share please

[@sayedmohdkazimmehdi7256]

console ninja

[@nodeSkin]

This man is just amazing !!!

[@sriramgudupuru1664]

I did a hit on like button, when i was at 17:11 ( setLIst( [...list, name ] ) ). Thank you so much master, for this vauable source

[@martinrombach2666]

Jack's a legend. Thanks for the pokeymon man.

[@kim92se64]

45 minutes watched BTW what a great Tutorial !!! awesome

[@juanmamani2110]

best 2:46 of the day! thanks for sharing!

[@vivekkumar-pc1xy]

you are the master of javascript

[@mazharansari7813]

I am on 1:13:40 and I was following along and everything was going fine but then the tutor switched to Typescript and starts teaching in it If they wanted to teach in Typescript they should sticked to it since the beginning or they should have notified that things will be taught in TS later in this course as a person who has no knowledge in TS now i have to learn it then i have come back to this course and resume this course it will just waste the time, for those who don't know TS

[@manfrombritain6816]

this is absolute gold

[@user-gf9ri4wj5h]

Masterpiece!

[@spikezkid022]

You know it's going to be a good React tutorial when the instructor doesn't use CRA

[@Bookwala12]

I already know this will be epic..

[@HammadUrRehman-gy9vs]

Great course, Just one correction In useRef section if we do "useState([{id: idRef.current++ , name:"john"} , {id: idRef.current++, name: "Jane"} ])" then upon every re-render idRef value gets updated two times, that maybe because of the development mode which follows "mount unmount and then again mount lifecycle". Note: "On second entry you will get the id 8 instead of 4"

[@mazharansari7813]

Thanks bro I was thinking about this

[@kharadinbrahman]

just found that out yesterday and commented. one better just set the numbers in the useState initial values.

[@rapelangmathibe8761]

im forever using use reducer for my forms

[@zombiefacesupreme]

Hey @jherr, this video is really incredible! Great job! Any idea why Beedrill is the first Pokemon on the useContext results at 1:40:22, but not on the Jotai results at 2:18:51? Is it because you sliced a different amount? I really like the atomic model. I'm gonna have to try Jotai out.

[@yukinosuketakada661]

because it slices before sorting

[@yukinosuketakada661]

shoud slice after sorting

[@adeleke5140]

Jack, please what's your font and your VSCode theme? thank you for the amazing tutorial

[@bengorman1722]

Thanks for the great video Jack! Regarding useReducer, the current React 18 docs examples declare the reducer function *outside* the component body. Besides reusability, is there any reason to do it this way as opposed to declaring the reducer *inside* the component?

[@gilberttorchon1280]

Excellent teacher!!!!

[@nicolafontana6376]

awesome video, does anyone knows what extension he uses for shortcuts in react (or more in general what do you guys would suggest?)

[@jpmitchell925]

This is actually gold

[@syedhaider0916]

Will keep this video for future reference. Thank you freecodecamp and jack. I just wish recoil was part of this video.

[@jherr]

Jotai is, and that is very close and IMHO better.

[@syedhaider0916]

@@jherrsir if you vouch for it, I will definitely definitely look into it.

[@kulyog6626]

Thank you very much Sir.

[@continuelearner4200]

Awesome.. Tutorial Jack... purely delighted... Thank you so much!!! Do you mind telling me what is the theme that you used in visual studio code... really liked it and how all keywords are italic... please help me on this

[@vanshgupta2763]

Hey Jack ! Awesome video man. Clear all the fundamentals in one shot. Can you let me know what VS Code extension you are using, that seems to be doing wonders as well.

[@nikhilranka9660]

Quokka.js is the one you are amazed by I guess. Or possibly, console-ninja

[@Ujedkemal]

did you get the answer dude? let me know if you did.

[@raafihilmi]

for auto complete? I think its Tabnine extensions

[@raafihilmi]

@@Ujedkemal for auto complete? I think its Tabnine extensions

[@JosephMaramba]

High quality intermediate to advanced React contect

[@spongebob93lover]

would love to see a tutorial about swr in terms of state management, and maybe compare it to react query

[@mariuszprzodaa8499]

Could you record a video about eventrix? It’s a new open source alternative for redux that our company created and we want to share our work with the world :)

[@wahajahmed2823]

One of the greate video. 🤩🤩

[@sumairimtiaz4545]

Superb course

[@Ujedkemal]

whats the extension he used? like when we want to type onClick function, the extension could show up the recomendation tag and symbol for typing the function.

[@christopherwilhoite7856]

Great vid!

[@husainahmadali8323]

Best instructor

[@Nir4023]

Good explanations, can anyone provide some advice about project structure/folders when building medium sized app using hooks for local state and context or maybe zustand for global state ? some boilerplate repo would be appreciated too

[@ThunderSlav]

Cca 17:30 Why not using the "prevState" for updating the array?

[@john-dolaspassiveincomestr9144]

My eye just pop open. Jack thanks

[@csabapadar9978]

"How coooool is thaaat?" :D

[@MegaJarvas]

Forgive me for not knowing exactly how to ask this but what is the tool used for the suggested autocomplete when coding?

[@beckaksel8783]

Hello, I love your videos about kivy)) I have a question: I will develop a mobile app and upload it to the Google Play. What do you think, can I use kivy or it is better to use java? Thank you)

[@learnfronteasy9642]

Hi, Thank you for your awesome video....what is your extension to complete code in react

[@natashaswan7731]

Does anybody know what Jack is using that gives prompts when he starts typing? For example, for reduce function syntax at 33min.11sec? What VS extension is it?

[@kharadinbrahman]

1:13:36 Jack, it gives an error as it is, useRef: it runs ok with values like 1, 2, 3... but then it comes obvious that the ++ increments in the useState are fired every time and the count increases by 5, if in strict mode, or by 3, if you comment out 'strict' mode., so what one can do is to assign numbers: id 1 and id 2 for John and Jane, and start the count with 3. (or 2 and pre-increment the id)

[@herreranicoo25]

Thanks for this!

[@amithanilgeorge4956]

Thanks for this,but i don't understand reason behind this ,is it because setting useState which lead to render this it results in increamenting refId more times?

[@ryan17stehle]

Can someone explain to me what Jack does around the 31 minute mark with the {...state, ...action}. I understand the spread operator syntax, I just can't wrap my head around how this works with a more complex state. Like if I had an array of people with first & last name, how would this shortened reducer function know which values to change? I've spent an hour+ trying to work this out.

[@chrisk5269]

Thanks!

[@ajit78910]

Thank you sir ❤🙏

[@rezaz7167]

what extensions are you using? how can you run typescript file apart from others (when you open typescript workbook 19:30) - how does the VSCode shows the result in front of the code?

[@jherr]

That's Quokka.

[@treyrader]

I am getting duplicate keys error in the useState segment. I wish he'd have explained the reason for introducing that prop rather than just add it as if serves seome necessary functionality. It breaks the app. Also, even after calling a blank string on setName, the input field still doesn't refresh.

[@anasouardini]

you always surprise me with the super white bg.

[@damianrebolo]

What is the name of the extension you use to auto fill specific lines? Thanks!

[@jherr]

GitHub Copilot

[@christiangubana]

I like your teaching technic

[@sahinnmaral]

I like the second implementation of useReducer hook but when I'm going to try with Typescript , I couldn't manage to implement. Is that my problem or is it possible to implement with Typescript ?

[@johndoe-si2sp]

can you share what extensions your are using on vscode?

[@Rvjonh]

goddddd amazing!!!

[@dhanviakash726]

Just after watching 15 mins, my mind be like 🤯😮‍💨 (how a man can make us to understand something into this level)

[@dhanviakash726]

@AKSHAY sorry I didn't get you.. As well as I am from south India, so I didn't understand Hindi in code with harry videos

[@dhanviakash726]

@AKSHAY hey by the way, do you know any best react native course.. 😁

[@nosrehcorporation]

Nice tutorrial, my only question is why Arcanine is not the first as it starts with A?

[@thomasstambaugh5181]

The shift to Typescript at 1:13:53 significantly impairs the rest of the video. The noise of all that Typescript junk obfuscates the material I'm trying to absorb. I apparently have to go elsewhere to learn how to use "useContext", "createContext" and custom hooks in Javascript.

[@apprendrelibrementlaprogra596]

Nice course

[@protocol4313]

How to get that no of time console log is rendered and result of code displayed when clicked on same line

[@BudetSvobodnoy]

on 28:35 wouldn't it be better to use forEach instead of map? Since map creates a new array which is not necessary here

[@moumitadhar3890]

Can anyone please explain the closure thing that Jack explained in UseEffect Hook ?