Create-react-app: No .jsx extension?

[MrSkinny]

Note from Maintainers

We support JSX extension since 0.4.1 even though we don’t recommend it.
Read the release notes.

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Shouldn't the default be to use .jsx extension in files where JSX is in use? As configured, the loader isn't set up to transpile jsx. Many code editors will provide better coloring/linting when detecting a .jsx file

[gaearon]

The distinction between .js and .jsx files was useful before Babel, but it’s not that useful anymore.

There are other syntax extensions (e.g. Flow). What would you call a JS file that uses Flow? .flow.js? What about JSX file that uses Flow? .flow.jsx? What about some other experimental syntax? .flow.stage-1.jsx?

Most editors are configurable so you can tell them to use a JSX-capable syntax scheme for .js files. Since JSX (or Flow) are strict supersets of JS, I don’t see this as an issue.

Am I missing something?

[gaearon]

I’ll close but if I missed something please let me know and I can reopen.

[vjeux]

@gaearon do you know if there's an easy way to have a clear error message when people try to write a jsx file? Something like "jsx extension is not supported with create-react-app [insert more...]" instead of failing with a cryptic error message as it currently is

[pungggi]

Most editors are configurable so you can tell them to use a JSX-capable syntax scheme for .js files.

Ok this makes sense.
But does anyone know how to accomplish that f. ex. in VisualStudioCode?

I have found this http://stackoverflow.com/questions/32832264/change-language-to-jsx-in-visual-studio-code

[gaearon]

do you know if there's an easy way to have a clear error message when people try to write a jsx file?

Yes, we can totally do it, it’s not hard.

But does anyone know how to accomplish that f. ex. in VisualStudioCode?

Let’s discuss that in #287. 👍

[tim-phillips]

Just wanted to call attention to the Airbnb style guide, they are still recommending .jsx file extensions. Airbnb most likely have their build tools sorted though.

For vim users, while using vim-javascript & vim-jsx you can add let g:jsx_ext_required = 0 to your .vimrc to allow for JSX syntax support in .js files.

EDIT: i'm just now seeing the reference above from airbnb/javascript#985

[gaearon]

Posted more thoughts on it: https://github.com/airbnb/javascript/pull/985#issuecomment-239145468

[gaearon]

FYI we support JSX extension since 0.4.1 even though we don’t recommend it.
Read the release notes.

[loopmode]

I find using a jsx extension useful, while not necessary, to instantly see which files can be shared across projects that may not be using babel or even react for that matter, without looking into the files.
I would never name a file that doesn't contain JSX syntax .jsx, e.g. utility modules, regular pure functions etc. For the same reasons I would never call a file that contains JSX syntax .js.
It is just a convention of course, as others may have explained already.

[gaearon]

which files can be shared across projects that may not be using babel

Don’t you find the notation inconsistent? For example, you can’t use many ES6 features without Babel if you intend to support older browsers. Even things like destructuring. But it’s weird to call a file using destructuring (or, for example, default arguments) .jsx because it doesn’t actually use JSX. At some point you may decide to stop supporting those browsers. At this point there is no reasonable explanation for why such file is called .jsx. By using .js uniformly you avoid these inconsistencies altogether.

[tim-phillips]

I just changed all my .jsx files to .js. I like how I'm starting to think of jsx as an extension of JavaScript rather than something separate.

[loopmode]

Ok I finally got the point.. The way I descibed it, I'd need to make sure that my .js files are actually all written in es5. A tedious task, and a useless one for long-living codebases. (Won't be necessary in near future). Tho it is a bit different with JSX syntax, which probably won't become standard javascript anytime soon, it's much simpler if we embrace it as a transpiler-feature just like destructuring etc.
So.. I guess I too will be changing all my .jsx files to .js soon :)

[turnerhayes]

I'm glad it now supports .jsx, but it appears to still be looking for index.js and not accepting index.jsx. Can that be fixed too?

[iDVB]

Out of google magic for this one. But why does createreactapp seem to enforce eslint:react/jsx-filename-extension if JSX files are not reco? https://github.com/facebookincubator/create-react-app/issues/87#issuecomment-234627904

All our files are .JS even the ones that contain JSX....we're using base createreactapp and unless I have waring IDE settings, it complaining about JSX not allowed in files with extension '.js'

[pikilon]

Typescript is also a superset and it uses .ts why JSX is not using his own extension?

[qodesmith]

The _only_ reason I use the .jsx extension is because without it, Github's syntax highlighting get's _red-lines-hightlighted-everywhere_ diarrhea. I can't stand looking at PR's like that.

[Qix-]

@qodesmith a bit late, but there's an open issue for that: github/linguist#3677

[esr360]

After pushing some code to bitbucket and seeing that the syntax highlighting was broken, I went to see why Atlassian don't support syntax highlighting of JSX; it turns out they do! But, perhaps naturally, the file extension must be .jsx (https://jira.atlassian.com/browse/BSERV-10700).

I was then reminded of this discussion, so wanted to chime in. I think it's totally reasonable for a syntax highlighter to not attempt to highlight syntax that isn't standard to language. It seems quite reasonable that if I want syntax to be highlighted as JSX, then the file should have the extension .jsx.

Thinking about it in this way actually makes me think having jsx syntax inside a .js file is unreasonable.

[mrmckeb]

TypeScript uses TSX - but personally I feel that enforcing JSX creates more overhead for developers. Most tools in the chain work fine with JSX in JS.

Of course, that doesn't mean you couldn't enforce that standard in your own projects @esr360.

[Timer]

For future searchers: we support both .js and .jsx.