vitejs/vite · error · Error

config must export or return an object.

Error message

config must export or return an object.

What it means

In loadConfigFromFile (config.ts:2424-2428), after evaluating the config export (calling it if it's a function), Vite checks isObject(config). If the config file exports/returns a non-object (e.g. a string, number, array, or undefined), it throws because a Vite config must be a plain object.

Source

Thrown at packages/vite/src/node/config.ts:2428

  try {
    const { configExport, dependencies } = await (configLoader === 'bundle'
      ? bundleAndLoadConfigFile(
          resolvedPath,
          configRoot,
          logLevel,
          customLogger,
        )
      : configLoader === 'runner'
        ? runnerImportConfigFile(resolvedPath)
        : nativeImportConfigFile(resolvedPath))
    debug?.(`config file loaded in ${getTime()}`)

    const config = await (typeof configExport === 'function'
      ? configExport(configEnv)
      : configExport)
    if (!isObject(config)) {
      throw new Error(`config must export or return an object.`)
    }

    return {
      path: normalizePath(resolvedPath),
      config,
      dependencies,
    }
  } catch (e) {
    const logger = createLogger(logLevel, { customLogger })
    checkBadCharactersInPath('The config path', 'file', resolvedPath, logger)
    logger.error(colors.red(`failed to load config from ${resolvedPath}`), {
      error: e,
    })
    throw e
  }
}

async function nativeImportConfigFile(

View on GitHub (pinned to 89620f09af)

Solutions

1. Ensure the config file exports a plain object: export default { ... } (or defineConfig(() => ({ ... }))).
2. If using a function form, make sure it returns an object, not an array or primitive.
3. Verify the default export is actually reached (no early return / re-export of a non-config).

Example fix

// before
export default [reactPlugin]
// after
import { defineConfig } from 'vite'
export default defineConfig({ plugins: [reactPlugin] })

import { isObject } from 'vite'
const cfg = typeof configExport === 'function' ? await configExport(env) : configExport
if (!isObject(cfg)) throw new Error('Config must export/return a plain object')

function isConfigObject(value: unknown): value is Record<string, any> {
  return typeof value === 'object' && value !== null && !Array.isArray(value)
}

When it happens

Trigger: A vite.config file whose default export or returned value is not an object — e.g. `export default 'vite'`, `export default 42`, a function that returns an array, or a file that exports nothing (undefined).

Common situations: Default export forgotten/typo'd; config file written as a list of plugins without wrapping in an object; a function config that returns the wrong shape; partial migration leaving an incomplete file.

Related errors

• `renderLegacyChunks` and `renderModernChunks` cannot be both
• Invalid environment name "${name}". Environment names must o
• `input` cannot contain glob characters. They are reserved, s
• Required environments configuration were stripped out in the
• The value passed to "base" option was malformed. It should b

AI-assisted analysis of vitejs/vite@89620f09af (2026-08-03). Data as JSON: /data/errors/d9e701684f345306.json. Report an issue: GitHub.