jackwener/OpenCLI · error · ArgumentError

npm ${label} cannot be empty

Error message

npm ${label} cannot be empty

What it means

requireString validates that a labeled argument is a non-empty string after trimming; when the value is null, undefined, or whitespace-only it throws ArgumentError `npm ${label} cannot be empty`. It is the first-line guard for CLI arguments like `query` in the search command, so malformed input fails fast before any network call.

Source

Thrown at clis/npm/utils.js:14

// Shared helpers for the npm adapters that hit the public npm registry
// (registry.npmjs.org) and download stats API (api.npmjs.org).
import { ArgumentError, CommandExecutionError, EmptyResultError } from '@jackwener/opencli/errors';

export const NPM_REGISTRY = 'https://registry.npmjs.org';
export const NPM_API = 'https://api.npmjs.org';
const UA = 'opencli-npm-adapter (+https://github.com/jackwener/opencli)';

// npm package names: 1-214 chars, lowercase letters/numbers/-._ , scoped form `@scope/name`.
const PKG_NAME = /^(?:@[a-z0-9][a-z0-9._-]*\/)?[a-z0-9][a-z0-9._-]*$/i;

export function requireString(value, label) {
    const s = String(value ?? '').trim();
    if (!s) throw new ArgumentError(`npm ${label} cannot be empty`);
    return s;
}

export function requirePackageName(value) {
    const s = String(value ?? '').trim();
    if (!s) throw new ArgumentError('npm package name is required (e.g. "react", "@vercel/og")');
    if (s.length > 214) {
        throw new ArgumentError(`npm package name "${value}" is too long (max 214 chars)`);
    }
    if (!PKG_NAME.test(s)) {
        throw new ArgumentError(
            `npm package name "${value}" is not a valid registry name`,
            'Names are 1–214 chars of lowercase a-z / 0-9 / "-._" (scoped form: "@scope/name").',
        );
    }
    return s;
}

View on GitHub (pinned to 49907e53dc)

Solutions

1. Pass the required argument, e.g. `npm search --query react` or `{ query: 'react' }` in code.
2. Check that the shell/CI variable supplying the value is non-empty before invoking.
3. Trim user input upstream and reject empty values with a clear message before calling the library.
4. Wrap calls in try/catch for ArgumentError to print friendly usage text instead of a stack trace.

Example fix

// before
await npmSearch({ query: process.env.Q }); // Q unset -> ArgumentError
// after
const q = (process.env.Q ?? '').trim();
if (!q) throw new Error('Set Q to a search term, e.g. Q=react');
await npmSearch({ query: q });

function ensureNonEmpty(v, label) {
  const s = String(v ?? '').trim();
  if (!s) throw new Error(`${label} is required`);
  return s;
}
const query = ensureNonEmpty(args.query, 'query');

function isNonEmptyString(v) {
  return typeof v === 'string' && v.trim().length > 0;
}

try {
  return await npmSearch({ query });
} catch (e) {
  if (e.name === 'ArgumentError') {
    console.error('Usage: npm search --query <term>');
    return null;
  }
  throw e;
}

When it happens

Trigger: Calling a command (e.g. `npm search`) without its required argument: args.query undefined because the flag was omitted, or passed as empty/whitespace (`--query ""`), or a programmatic caller passing null/undefined.

Common situations: Forgot `--query` on the CLI; shell variable holding the query was unset/empty (`--query "$Q"` with Q empty); empty value from a CI variable; scripting the command and forgetting the field.

Related errors

• series_id must be a non-empty value
• Invalid Chess.com username "${value}" Usernames are 3-25 cha
• coingecko derivatives limit must be a positive integer
• limit must be a positive integer
• Search keyword cannot be empty

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/cc70aad74ab5362f. Report an issue: GitHub.