jestjs/jest · error · ValidationError

● Validation Error: Configuration in ${packageJson} is no

Error message

● Validation Error:

  Configuration in ${packageJson} is not valid. Jest expects the string configuration to point to a file, but ${absolutePath} is not. Please check your Jest configuration in ${packageJson}.

What it means

Thrown as a ValidationError when a package.json contains a 'jest' key whose value is a string (intended as a pointer to a config file) but that string does not resolve to an actual file. The string can be relative (resolved against the package.json's directory) or absolute; isFile must return true.

Source

Thrown at packages/jest-config/src/resolveConfigPath.ts:89

  skipMultipleConfigError: boolean,
): string => {
  const configFiles = JEST_CONFIG_EXT_ORDER.map(ext =>
    path.resolve(pathToResolve, getConfigFilename(ext)),
  ).filter(isFile);

  const packageJson = findPackageJson(pathToResolve);

  if (packageJson) {
    const jestKey = getPackageJsonJestKey(packageJson);

    if (jestKey) {
      if (typeof jestKey === 'string') {
        const absolutePath = path.isAbsolute(jestKey)
          ? jestKey
          : path.resolve(pathToResolve, jestKey);

        if (!isFile(absolutePath)) {
          throw new ValidationError(
            `${BULLET}Validation Error`,
            `  Configuration in ${chalk.bold(packageJson)} is not valid. ` +
              `Jest expects the string configuration to point to a file, but ${absolutePath} is not. ` +
              `Please check your Jest configuration in ${chalk.bold(
                packageJson,
              )}.`,
            DOCUMENTATION_NOTE,
          );
        }

        configFiles.push(absolutePath);
      } else {
        configFiles.push(packageJson);
      }
    }
  }

  if (!skipMultipleConfigError && configFiles.length > 1) {

View on GitHub (pinned to 8e6d128e4a)

Solutions

Create the file the string points to, or fix the path in package.json
If you want inline config, change the 'jest' value to an object instead of a string
Verify with ls that the resolved absolute path is a file

Example fix

// before: package.json
{
  "jest": "./config/jest.base.js"
}
// (file does not exist)

// after: create the file, or fix the path
{
  "jest": "./jest.config.js"
}

Defensive patterns

Strategy: validation

Validate before calling

import * as fs from 'node:fs';
import * as path from 'node:path';
function assertPackageJsonJestKey(pkgPath: string): void {
  const pkg = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
  if (typeof pkg.jest === 'string') {
    const abs = path.isAbsolute(pkg.jest)
      ? pkg.jest
      : path.resolve(path.dirname(pkgPath), pkg.jest);
    if (!fs.existsSync(abs) || fs.lstatSync(abs).isDirectory()) {
      throw new Error(`jest key in ${pkgPath} does not point to a file: ${abs}`);
    }
  }
}

Type guard

function isFilePointer(value: unknown, baseDir: string): boolean {
  if (typeof value !== 'string') return false;
  const abs = path.isAbsolute(value) ? value : path.resolve(baseDir, value);
  return fs.existsSync(abs) && !fs.lstatSync(abs).isDirectory();
}

Prevention

Prefer an inline object or a dedicated jest.config.* file over a string pointer
When renaming config files, grep package.json for the old path
In monorepos, use per-workspace configs rather than cross-package string pointers

When it happens

Trigger: Setting "jest": "./jest.config.js" in package.json when that file does not exist, or pointing to a directory rather than a file, or a typo in the relative path.

Common situations: Renaming/deleting the referenced config without updating package.json; monorepo where the relative path is correct in one package but copied to another with a different layout; pointing 'jest' at a folder.

Related errors

AI-assisted analysis of jestjs/jest@8e6d128e4a (2026-08-10). Data as JSON: /api/errors/5ca7fdf17081a3e4. Report an issue: GitHub.