vitejs/vite · error · Error

Failed to parse WASM file "${wasmFilePath}": ${(e as Error).

Error message

Failed to parse WASM file "${wasmFilePath}": ${(e as Error).message}

What it means

parseWasm (packages/vite/src/node/plugins/wasm.ts:241) reads the .wasm file, calls WebAssembly.compile with Vite's wasm-compiled-options (js-string builtins), then enumerates Module.imports/exports to generate glue code. Any failure — corrupt bytes, unsupported proposal, or a compile error — is re-thrown with the original as `cause` and the file path in the message.

Source

Thrown at packages/vite/src/node/plugins/wasm.ts:263

    const importMap = new Map<string, WasmName[]>()
    for (const item of WebAssembly.Module.imports(wasmModule)) {
      if (wasmReservedModules.has(item.module)) continue
      let names = importMap.get(item.module)
      if (!names) importMap.set(item.module, (names = []))
      names.push({ name: item.name, isGlobal: item.kind === 'global' })
    }
    const imports = [...importMap].map(([from, names]) => ({ from, names }))

    let hasGlobalExport = false
    const exports = WebAssembly.Module.exports(wasmModule).map((item) => {
      const isGlobal = item.kind === 'global'
      if (isGlobal) hasGlobalExport = true
      return { name: item.name, isGlobal }
    })

    return { imports, exports, hasGlobalExport }
  } catch (e) {
    throw new Error(
      `Failed to parse WASM file "${wasmFilePath}": ${(e as Error).message}`,
      { cause: e },
    )
  }
}

// Instantiates the wasm module and re-exports its exports verbatim. Globals stay
// WebAssembly.Global objects so wasm-to-wasm global imports get the live cell.
function generateInstanceGlue(
  wasmInfo: WasmInfo,
  names: { initWasm: string; wasmUrl: string },
): string {
  const importStatements: string[] = []
  const importObject: SimpleObject = wasmInfo.imports.map(
    ({ from, names: importNames }, i) => {
      const value: SimpleObject = []
      const globals = importNames.filter((n) => n.isGlobal)
      const others = importNames.filter((n) => !n.isGlobal)

View on GitHub (pinned to 89620f09af)

Solutions

1. Re-build/re-download the .wasm so its bytes are complete and valid; verify with `node -e "WebAssembly.compile(require('fs').readFileSync('x.wasm'))"`.
2. Use a Node version that supports the wasm proposals the module was compiled with (check the release that introduced js-string builtins / the proposal in question).
3. Confirm the file is actually WebAssembly (`file x.wasm` / check magic bytes \0asm) and that Vite resolves the path you expect.
4. If you do not need Vite's glue generation, import the wasm via ?init and instantiate it manually so parseWasm is bypassed.

Example fix

// before: direct import triggers parseWasm and fails on an old Node
import wasm from './asset.wasm'

// after: validate/upgrade the toolchain, then keep the import
//   node --version  # upgrade to a release with the needed proposal
//   wasm-pack build --target web
import wasm from './asset.wasm'

import { readFileSync } from 'node:fs'
function wasmLooksValid(file: string): boolean {
  const b = readFileSync(file)
  return b.length >= 8 && b[0] === 0x00 && b[1] === 0x61 && b[2] === 0x73 && b[3] === 0x6d
}
if (!wasmLooksValid('asset.wasm')) throw new Error('not a valid wasm file')

function isWasmMagic(bytes: Uint8Array): boolean {
  return bytes[0] === 0x00 && bytes[1] === 0x61 && bytes[2] === 0x73 && bytes[3] === 0x6d
}

try {
  await import('./asset.wasm')
} catch (e) {
  if (/Failed to parse WASM file/.test((e as Error).message)) {
    // rebuild wasm artifact / upgrade Node, then retry build
  }
  throw e
}

When it happens

Trigger: Importing a .wasm that is truncated/corrupt; a wasm built with a proposal your host Node version does not support; a non-wasm file accidentally named .wasm; a wasm whose imports reference modules the engine rejects during Module.imports inspection.

Common situations: Bumping @vitejs/plugin-wasm or the toolchain that emits wasm (wasm-pack, emscripten, assemblyscript) to a version using newer proposals; checking out a repo with a stale or partially-downloaded .wasm artifact; case-sensitivity issues on Linux pointing at a non-existent file that fsp.readFile rejects.

Related errors

• Cannot use "sourcemapInterceptor: 'node'" because "process.s
• No environment found
• Either "build.lib.entry" or the top-level "input" option is
• rolldownOptions.input should not be an html file when buildi
• When "build.cssCodeSplit: false" is set, "rolldownOptions.in

AI-assisted analysis of vitejs/vite@89620f09af (2026-08-03). Data as JSON: /data/errors/95835fce87442db6.json. Report an issue: GitHub.