jestjs/jest · error · Error

The --selectProjects option requires the name of at least on

Error message

The --selectProjects option requires the name of at least one project to be specified.
Example usage: jest --selectProjects my-first-project my-second-project

What it means

`check` throws (packages/jest-cli/src/args.ts:63) when `--selectProjects` is supplied but the array is empty. selectProjects filters the `projects` config by `displayName`, so at least one name is required or the filter matches nothing.

Source

Thrown at packages/jest-cli/src/args.ts:64

        'Example usage: jest --findRelatedTests ./src/source.js ' +
        './src/index.js.',
    );
  }

  if (
    Object.prototype.hasOwnProperty.call(argv, 'maxWorkers') &&
    argv.maxWorkers === undefined
  ) {
    throw new Error(
      'The --maxWorkers (-w) option requires a number or string to be specified.\n' +
        'Example usage: jest --maxWorkers 2\n' +
        'Example usage: jest --maxWorkers 50%\n' +
        'Or did you mean --watch?',
    );
  }

  if (argv.selectProjects && argv.selectProjects.length === 0) {
    throw new Error(
      'The --selectProjects option requires the name of at least one project to be specified.\n' +
        'Example usage: jest --selectProjects my-first-project my-second-project',
    );
  }

  if (argv.ignoreProjects && argv.ignoreProjects.length === 0) {
    throw new Error(
      'The --ignoreProjects option requires the name of at least one project to be specified.\n' +
        'Example usage: jest --ignoreProjects my-first-project my-second-project',
    );
  }

  if (
    argv.config &&
    !isJSONString(argv.config) &&
    !new RegExp(
      `\\.(${constants.JEST_CONFIG_EXT_ORDER.map(e => e.slice(1)).join('|')})$`,
      'i',

View on GitHub (pinned to f49721c78e)

Solutions

1. Pass one or more project display names: `jest --selectProjects app-server web-client`.
2. Guard the invocation when the name list is dynamic: `[ -n "$PROJECTS" ] && jest --selectProjects $PROJECTS`.
3. Verify the names match `displayName` values in your jest.config projects array.

Example fix

# before
jest --selectProjects

# after
jest --selectProjects my-first-project my-second-project

function requireProjectNames(names?: string[]): string[] {
  if (!names || names.length === 0) throw new Error('--selectProjects needs >=1 displayName');
  return names;
}

const hasProjectNames = (a: any) => Array.isArray(a.selectProjects) && a.selectProjects.length > 0;

When it happens

Trigger: `jest --selectProjects` with no project names following it; a script that expands `$PROJECTS` where the variable is empty.

Common situations: CI matrix scripts that conditionally set project names but run unconditionally; shell quoting that swallows the list.

Related errors

• The --ignoreProjects option requires the name of at least on
• Both --runInBand and --maxWorkers were specified, only one i
• Both --${key} and --watchAll were specified, but cannot be u
• Both --onlyFailures and --watchAll were specified, only one
• The --findRelatedTests option requires file paths to be spec

AI-assisted analysis of jestjs/jest@f49721c78e (2026-08-03). Data as JSON: /data/errors/586aaf13e5a295a1.json. Report an issue: GitHub.