module: support Wasm without file extension within module scope
#49540
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Review requested:
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nodejs-github-bot
added
errors
| fd = openSync(url); | ||
| readSync(fd, magic); | ||
| if (magic[0] === 0x00 && magic[1] === 0x61 && magic[2] === 0x73 && magic[3] === 0x6d) { | ||
| return 'wasm'; | ||
| } |
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I get that we’re just reading the first four bytes here (I think?) but doesn’t doing this here mean that we open and read the file twice? Once to detect format and again later to actually run it?
Especially since this happens for every ESM entry point, even JavaScript ones, this feels like a performance regression that we should avoid.
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This happens only for extensionless files, right? If that's the case, that seems absolutely OK as a tradeoff, the workaround is to use the .mjs extension.
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That's correct, the check is only for local extensionless files in module scope.
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Why do we need a tradeoff? Can’t we keep the file contents in memory once we have them, so that later on when the load hook runs it uses the contents from memory rather than refetching them from disk?
| export function jsInitFn () { | ||
| strictEqual(state, 'JS Function Executed'); | ||
| state = 'WASM Start Executed'; | ||
| } |
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Closing now that #49974 has landed. |
d78a9da blocked on #49531