Spread children not supported

const F = () => <a>{...[]}</a>;

crashes sucrase with:

Error transforming sample.tsx: Unterminated regular expression (1:29)

[alangpierce]

I just released a fix for this in 3.10.0.

[yang]

Yeah I’m using React. FWIW this is syntax that Typescript supported. My understanding of this syntax is that it’s for places where you have an array but know it’s actually static and unchanging, so that keys are not necessary (so React can spread them out as if they were positional args to createElement). It’s also useful when you’re transplanting children from one place to another.

I don’t know why Babel chokes on this, though I’ve seen a higher rate of bugs in Babel than TSC so far since the switch in create react app 2.0 (random example).

Thanks!

On Fri, Feb 22, 2019 at 7:14 AM Alan Pierce [e-mail] wrote:

Interesting, I actually hadn’t seen that syntax. FWIW, Babel (with the React transform) throws an exception, saying “Spread children are not supported in React” (repl https://babeljs.io/repl#?babili=false&browsers=&build=&builtIns=false&spec=false&loose=false&code_lz=FAYw9gdgzgLgBAMTgXjgCgJQoHxwDwCG2A3gHTkDaAugL54D0RA3EA&debug=false&forceAllTransforms=false&shippedProposals=false&circleciRepo=&evaluate=false&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=es2015%2Creact%2Cstage-2&prettier=false&targets=&version=7.3.3). Are you using something other than React? I think React wants you to pass an array there so it knows to check that you’re using keys properly.

Regardless, I think it’s within Sucrase’s scope to just compile it and let other tools do the error checking, so this certainly seems reasonable to implement.

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