Function loadConfigFromFile

packages/vite/src/node/config.ts:2296–2373

(
  configEnv: ConfigEnv,
  configFile?: string,
  configRoot: string = process.cwd(),
  logLevel?: LogLevel,
  customLogger?: Logger,
  configLoader: 'bundle' | 'runner' | 'native' = 'bundle',
)

}

export async function loadConfigFromFile(
  configEnv: ConfigEnv,
  configFile?: string,
  configRoot: string = process.cwd(),
  logLevel?: LogLevel,
  customLogger?: Logger,
  configLoader: 'bundle' | 'runner' | 'native' = 'bundle',
): Promise<{
  path: string
  config: UserConfig
  dependencies: string[]
} | null> {
  if (
    configLoader !== 'bundle' &&
    configLoader !== 'runner' &&
    configLoader !== 'native'
  ) {
    throw new Error(
      `Unsupported configLoader: ${configLoader}. Accepted values are 'bundle', 'runner', and 'native'.`,
    )
  }

  const start = performance.now()
  const getTime = () => `${(performance.now() - start).toFixed(2)}ms`

  let resolvedPath: string | undefined

  if (configFile) {
    // explicit config path is always resolved from cwd
    resolvedPath = path.resolve(configFile)
  } else {
    // implicit config file loaded from inline root (if present)
    // otherwise from cwd
    for (const filename of DEFAULT_CONFIG_FILES) {
      const filePath = path.resolve(configRoot, filename)
      if (!fs.existsSync(filePath)) continue

      resolvedPath = filePath
      break
    }
  }

  if (!resolvedPath) {
    debug?.('no config file found.')
    return null
  }

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

    const config = await (typeof configExport === 'function'