The tsconfig file has always been one of the hardest parts to figure out in TypeScript. Thank you for your explanation.

This is gold, really some options I missed. Thank you

Super useful! Thanks Matt!

That is exactly what I need right now. Thank you Matt! 😊

So useful! I'd also love a short one on jsx options

Great stuff! Can you also do follow-up video on these video on using tsconfig for monorepos? For example what properties should go in the root config, what in some shared config and what config for the lib/apps themselves.

Thanks, I never know what to put in the TSConfig when I'm making libraries and always seem to screw one of those up. Will be referring to this over and over again!

Got this recommended to me again. What a huge boon. This should be at the start of every TS tutorial. Thank you for making our lives easier EDIT: I made a comment about tsx (executable not JSX!) but I didn't realize you also mentioned it here! My bad. But seriously though that little gem has eluded me for sooo long but it's so helpful. I don't think I've seen much discussion about it (I always see ts-node). Or maybe there are but they're just not showing because of how unfortunately named it is 😅

Thank you for your work. Very helpful!

this video is gold.

Thanks for the video 👍

Thanks Matt, I was literally struggling to copy some random tsconfig file for my side project right now.

One of the main reasons I hate TS is the config file nightmare 😂😂

Shared with the engineering team, thanks Matt, this is great

THANK YOU

Amen on the strict: true it's been my recommendation for years now ! 😂😂😂 Hopefully more and more people adopt it

always using webpack together with babel to transpile, using tsc as the commande to transpile. Seems to me the most complete way to target most of the bowser's release

Instant click, this is such a pain point. I'm always clueless about it every time I start a new TS project lol

This is useful

Thanks, tsconfig is a big pain in monorepos.

I’ve been digging into the tsconfig extensively during last couple of days and your cheatsheet has been very important source of information. I’ve got couple of questions though: 

 The main question: 
 Why do we need to set options for things that seem to be related to compilation via Typescript compiler when we DON’T use Typescript for compilation? What I mean - 
target “Sets the JavaScript language version for emitted JavaScript”. I understand that this applies when using Typescript for compilation. When NOT USING Typescript for compilation, (for example when using Next.js), why do I need target to be set?
Similar with modules - it determines the module system for emitted JS when using Typescript compiler (at least in my understanding). Again, why do I need this when Next.js/SWC does compilation? 

 Side questions: 
 - “skipLibCheck” should be “true” so the .d.ts files in node_modules won’t be checked - if I have exclude: [‘node_modules’], do I still need this? - when using allowJs, do you recommend checkJS or not?

Would be interesting to look at config files for sveltekit, next, vue etc

For all the times I've been crying internally "SOMEBODY just tell me what to set in this *!_^$#*@# FILE" - Bless you sir !

Looks like I'm doing some things incorrectly in my config, thanks Matt!

For anyone who get the "error TS1286: ESM syntax is not allowed in a CommonJS module when 'verbatimModuleSyntax' is enabled.", you just need to make sure that the package.json has "type":"module" set.

You are not the hero we deserved but better

Kind of new to typescript, what do you think of useUnknownInCatchVariables?

Nice video. I also think that strict: true is must have. But what i dont understand is why for exampl nest.js is not strict by default. Any explanation for that?

God bless u

If I'm building a library/framework that I want to be used by projects that can be run in either node or browser (and I want different behavior from it based on that), what do you recommend I set `lib` option to? Include `dom` and `dom.iterable` and then do runtime checks if they are available?

Do you have any tips on migrating a legacy code base to strict mode? I have tried an eslint plugin and a TS plugin with not desireable result (the TS plugin had a tendency to kill the TS server)

What do you recommend for setting up path aliases with nodenext?

are some of these needed when using tsup ?

Is there any list which "lib" version like "es2022" is available and supported by bun?

Matt! I'm trying to make a wrapper over a wrapper (over a wrapper...) over some data storage. A link to a playground with a very simplified version will be in the comments. When I return the inner wrapper, autocomplete and everything works fine. When I add a default value, the result is the same. When I try to use the default value inside a wrapper, TypeScript throws errors because it sees the union and not the exact wrapper type. I would appreciate it if you could show me how to convince TS that everything is ok (without using "as")

i dont add "lib" and "types" inside the tsconfig, instead: - i make an `env.d.ts` - for libs i use `/// ` and others stuff in the file - and for types, i just import them, like: `import "@total-typescript/ts-reset"`, `import "bun-types"` and stuff this ^ way i can just copy paste tsconfig files. because everything environment specific are inside `env.d.ts` now also i use these a lot too: "noUncheckedIndexedAccess": true, "noPropertyAccessFromIndexSignature": true, "exactOptionalPropertyTypes": true

For monorepo, do you also add declaration:true? Or this is only for « simple » library?

So, are the options of "If transpiling with TypScript" (moduleResolution, module, outDir, sourceMap) no needed if the transpiling is done by esbuild instead of tsc? I have a Vite (v5) project and I want to know if I should add or not those options.

Don't you need the `composite` only when using `references`? Or am I missing something?

I would love a video on the mess that is JSX, i know thay when i was looking into it it was really hard to understand what was foing on.

I think it's worth noting that none (?) of the Rust/Go based bundlers (SWC, tsup/esbuild) support emitting declaration maps, which makes building libraries with these tools a bit annoying in a mono repo setting, for the reason you mentioned with go to reference. If anyone knows how to get declarationMap to work with a fast bundler, please educate me.

Is there any tool that does that automatically with sane defaults?

What options would you recommend when using tsc solely to type check a JS repo that uses JSDoc?

what does "moduleResolution":"bundler" even do? Last time I messed around with that this option did not exist.

Having decalarationMap didn't help my VSCode to navigate to the actual source code and not to the build .d.ts files 😬 Help on this?

declarationMap didn't work in our Monoreo project.

Numpty award for the day... when I tried to cut-n-paste an option off of the screen! :/

incrementalCompilation? Missed?

I still want a way to say "Here is a string that is the content of a typescript file, strip it of all the typescript type system, and return the valid javascript" method or process.. Rather than point TSC at a file, and it create another file somewhere else.. I want a string in, string out... Still waiting for this to happen..

JavaScript has many problems, but all the damn config files are definitely one of its worst

Don't teach people to cheat! PS: I still need your head size.

noUnusedLocals and noUnusedParameters - should be turned off - you have eslint for that. noUncheckedIndexedAccess - is turned off on perpoise and you don't need to turn it on. exactOptionalPropertyTypes - not covered in the video, you should turn it on. Also explanations in video are unclear - didn't get anything new from it.

I never use strict: true - it gets in the way, and I know what's gonna be nullish or not in my codebase 😜

Strict false 😅