Export `fileToUrl` function for plugins

Clear and concise description of the problem

Vite’s some internal plugins uses the internal helper function fileToUrl, which emits asset file to dev-server/bundle and return a URL for using in generated module code. It’s also very useful for external plugins to emit asset files.

Suggested solution

Export fileToUrl function from Vite and document it in the docs.

Alternative

Plugin authors could copy the code from fileToUrl from their plugins. This is very inelegant.

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn’t already an issue that request the same feature to avoid creating a duplicate.

[Menci]

I’m working on a plugin bringing WebAssembly ESM integration to Vite, which is equivalent to Webpack’s asyncWebAssembly.

I need to emit the WASM file just like the internal wasm plugin but I have no way to do it. My workaround is calling the original plugin’s load function, which is inelegant and won’t work for other types of files (for those without a internal plugin in Vite that emits the file directly).

https://github.com/Menci/vite-plugin-wasm/blob/e501eb234ad22d81d9bc94cb20086b759b4b07df/src/index.ts#L50-L52

[sapphi-red]

If it’s in JS, I think import url from './something.js?url' could be used for now.

@Menci For example for your plugin, I guess this part https://github.com/Menci/vite-plugin-wasm/blob/d98e0384950b6aea3156031a17ae65d28bbc7abd/src/index.ts#L37-L57 could be like

`
import __wasmUrl from "${id}?url"
import __vite__initWasm from "${wasmHelper.id}"
${imports
  .map(
    ({ from, names }, i) =>
      `import { ${names.map((name, j) => `${name} as __vite__wasmImport_${i}_${j}`).join(", ")} } from ${JSON.stringify(
        from
      )};`
  )
  .join("\n")}
const __vite__wasmModule = await __vite__initWasm({ ${imports
        .map(
          ({ from, names }, i) =>
            `${JSON.stringify(from)}: { ${names.map((name, j) => `${name}: __vite__wasmImport_${i}_${j}`).join(", ")} }`
        )
        .join(", ")} }, __wasmUrl});
${exports
  .map(name => `export ${name === "default" ? "default" : `const ${name} =`} __vite__wasmModule.${name};`)
  .join("\n")}
`;

or

`
import __vite__initWasm from "${id}?init"
${imports
  .map(
    ({ from, names }, i) =>
      `import { ${names.map((name, j) => `${name} as __vite__wasmImport_${i}_${j}`).join(", ")} } from ${JSON.stringify(
        from
      )};`
  )
  .join("\n")}
const __vite__wasmModule = await __vite__initWasm({ ${imports
        .map(
          ({ from, names }, i) =>
            `${JSON.stringify(from)}: { ${names.map((name, j) => `${name}: __vite__wasmImport_${i}_${j}`).join(", ")} }`
        )
        .join(", ")} });
${exports
  .map(name => `export ${name === "default" ? "default" : `const ${name} =`} __vite__wasmModule.${name};`)
  .join("\n")}
`;