Module Resolution: imports with JSON assertion should not need flag when module is esnext

Demo Repo

https://github.com/tminuscode/resolve-json-module

Which of the following problems are you reporting?

The module specifier resolves at runtime, but not at build time

Demonstrate the defect described above with a code sample.

import htmlTags from 'html-tags/html-tags.json' assert { type: 'json' }

const keys = Object.keys(htmlTags)

Run tsc --showConfig and paste its output here

{
"compilerOptions": {
"target": "es2020",
"module": "esnext",
"moduleResolution": "node16"
},
"files": [
"./index.ts"
]
}

Run tsc --traceResolution and paste its output here

https://pastebin.com/GzfXrXi4

Sorry, content too long

Paste the package.json of the importing module, if it exists

{
"name": "resolve-json-module",
"dependencies": {
"html-tags": "^3.3.1",
"typescript": "^5.1.6"
}
}

Paste the package.json of the target module, if it exists

{
"name": "html-tags",
"version": "3.3.1",
"description": "List of standard HTML tags",
"license": "MIT",
"repository": "sindresorhus/html-tags",
"funding": "https://github.com/sponsors/sindresorhus",
"author": {
"name": "Sindre Sorhus",
"email": "sindresorhus@gmail.com",
"url": "https://sindresorhus.com"
},
"engines": {
"node": ">=8"
},
"scripts": {
"test": "xo && ava && tsd"
},
"files": [
"index.js",
"index.d.ts",
"void.js",
"void.d.ts",
"html-tags.json",
"html-tags-void.json"
],
"keywords": [
"html",
"html5",
"tags",
"elements",
"list",
"whatwg",
"w3c",
"void",
"self-closing"
],
"devDependencies": {
"ava": "^1.4.1",
"tsd": "^0.7.2",
"xo": "^0.24.0"
},
"xo": {
"rules": {
"import/extensions": "off"
}
}
}

Any other comments can go here

I wan to use the latest ES feature of asserted imports to directly load a JSON from the package html-tags. The feature requires targeting esnext and I expected it to be enough, given the no compilation actually happens - the syntax is exactly the same in TS and JS

However, to actually make tsc happy, it is necessary to add --resolveJsonModule --allowSyntheticDefaultImports. Without these two, I'm getting these errors

error TS2732: Cannot find module 'html-tags/html-tags.json'. Consider using '--resolveJsonModule' to import module with '.json' extension.

resolveJsonModule seems completely redundant because importing JSON is supported per assert { type: 'json' }

error TS1259: Module '"/Volumes/Home/projects/temp/resolve-json-module/node_modules/html-tags/html-tags"' can only be default-imported using the 'allowSyntheticDefaultImports' flag
[...]
This module is declared with 'export =', and can only be used with a default import when using the 'allowSyntheticDefaultImports' flag.

I'm not sure about this. Isn't default-import the only way to import a JSON file?

Commencez par la démo resolve-json-module liée et sa reproduction index.ts ; exécutez tsc avec les paramètres es2020, esnext et node16 indiqués, puis comparez la sortie de tsc --showConfig et --traceResolution avec et sans les flags. C’est terminé lorsque l’import JSON indiqué passe le contrôle de typage sans resolveJsonModule ni allowSyntheticDefaultImports, tout en préservant la syntaxe compatible avec le runtime signalée.