Fix auto imports in JS files in nodenext #54817
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For Milestone Bug
| // @Filename: /totally-irrelevant-no-way-this-changes-things-right.js | ||
| //// export default 0; |
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We were using the presence of ES module syntax in other files as an indicator of what to use, but --module nodenext is a stronger signal—we should default to syntax that won’t crash in Node.
| if (sourceFile.impliedNodeFormat === ModuleKind.CommonJS) return true; | ||
| if (sourceFile.impliedNodeFormat === ModuleKind.ESNext) return false; | ||
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| // 5. Match the first other JS file in the program that's unambiguously CJS or ESM | ||
| for (const otherFile of program.getSourceFiles()) { | ||
| if (otherFile === sourceFile || !isSourceFileJS(otherFile) || program.isSourceFileFromExternalLibrary(otherFile)) continue; | ||
| if (otherFile.commonJsModuleIndicator && !otherFile.externalModuleIndicator) return true; | ||
| if (otherFile.externalModuleIndicator && !otherFile.commonJsModuleIndicator) return false; |
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when checking with other file, would it be better to check their implied node format as well to determine what this file probably is supposed to be.
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Because of the new checks I added, all files in the program are guaranteed to have an undefined impliedNodeFormat at this point in the code. impliedNodeFormat is always set to one of the two options I checked for, or else it’s not used at all in the program’s module mode.
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Isnt it set by looking up package.json in ancestor directory so is it not possible to have impliedNodeFormat not set on one file vs other ?
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If no package.json is found, it defaults to CJS. (This reflect’s Node’s behavior too. The choice is binary; the field is only optional because it’s not used outside of --module nodenext.)
Fixes #54350