quasarframework/quasar · warning

No valid env prefix specified in the array, using default "$

Error message

No valid env prefix specified in the array, using default "${defaultPrefix}" instead.

What it means

getEnvFilesPrefix validates the `envFilesPrefix` array (from quasar.config > build > envFilesPrefix) and falls back to a default prefix when none of the entries is a valid JS identifier. This warning is emitted instead of failing so builds keep working, but the user's intended prefix is ignored. It exists because Quasar needs a valid identifier to expose env keys in process.env on the client.

Source

Thrown at app-vite/lib/utils/env.js:99

        `Invalid env prefix "${entry}" specified in the array. Skipping it.`,
        banner
      )
      continue
    }

    validPrefixList.push(entry)
  }

  if (validPrefixList.length === 0) {
    if (!defaultPrefix) {
      warn(
        `No valid env prefix specified in the array. Allowing all env keys that are valid in JS (without any prefix).`,
        banner
      )
      return ''
    }

    warn(
      `No valid env prefix specified in the array, using default "${defaultPrefix}" instead.`,
      banner
    )
    return defaultPrefix
  }

  return validPrefixList
}

function convertFileToArray(value) {
  if (Array.isArray(value)) return value
  return typeof value === 'string' ? [value] : []
}

function convertFolderToArray(value, appDir) {
  if (Array.isArray(value)) return value.length !== 0 ? value : [appDir]
  return typeof value === 'string' ? [value] : [appDir]
}

View on GitHub (pinned to 4841521b5f)

Solutions

1. Use prefixes that are valid JS identifiers: letters, digits, underscore, not starting with a digit (e.g. ['MY_APP', 'VUE_APP']).
2. If you intended to allow all env keys, pass an explicitly empty configuration path the library supports (the preceding branch returns '' with its own warning) rather than invalid entries.
3. Re-run the dev/build command and confirm the warning no longer appears and process.env keys resolve in client code.

Example fix

// before (quasar.config)
build: { envFilesPrefix: ['my-app-env', '2nd-prefix'] }
// after
build: { envFilesPrefix: ['MY_APP_ENV', 'SECOND_PREFIX'] }

const identifiers = (cfg.build?.envFilesPrefix ?? []).filter(p => typeof p === 'string' && /^[A-Za-z_$][A-Za-z0-9_$]*$/.test(p));
if (identifiers.length === 0) throw new Error('envFilesPrefix has no valid JS identifiers');

const isValidPrefix = (p) => typeof p === 'string' && /^[A-Za-z_$][A-Za-z0-9_$]*$/.test(p);

When it happens

Trigger: Setting build.envFilesPrefix to an array containing only invalid JS identifiers (e.g. ['my-env', '123abc', 'with-dash']) or an array of non-string values; then calling getEnvFilesPrefix via prefix/clientPrefix/backendPrefix.

Common situations: Typos like dashes or leading digits in the prefix; copying a kebab-case env var name (APP-MY_KEY) into the config; passing process.env keys rather than the prefix portion.

Related errors

• Build output directory must be a non-empty path
• Project directory must be a non-empty path
• Invalid SSR nonce. Expected a non-empty base64 or base64url
• [Quasar] In your Vite config file, please add the Quasar plu
• Failed to open specific browser

AI-assisted analysis of quasarframework/quasar@4841521b5f (2026-08-30). Data as JSON: /api/errors/13ed3875271465ef. Report an issue: GitHub.