jackwener/OpenCLI · error · ArgumentError

wikipedia page title cannot be empty

Error message

wikipedia page title cannot be empty

What it means

The `wikipedia page` command requires a positional article title. If args.title is missing, null, or only whitespace after trimming, the command's func throws an ArgumentError immediately before any network call, because a title-less query cannot produce a meaningful API request.

Source

Thrown at clis/wikipedia/page.js:30

cli({
    site: 'wikipedia',
    name: 'page',
    access: 'read',
    description: 'Full plain-text extract of a Wikipedia article (optional paragraph cap).',
    domain: 'wikipedia.org',
    strategy: Strategy.PUBLIC,
    browser: false,
    args: [
        { name: 'title', positional: true, required: true, type: 'string', help: 'Article title (e.g. "Transformer (machine learning model)")' },
        { name: 'lang', type: 'string', default: 'en', help: 'Language code (en, zh, ja, de, ...).' },
        { name: 'paragraphs', type: 'int', default: 0, help: 'Cap to first N paragraphs (0 = full article).' },
    ],
    columns: ['title', 'description', 'pageId', 'paragraphs', 'extract', 'url'],
    func: async (args) => {
        const title = String(args.title ?? '').trim();
        if (!title) {
            throw new ArgumentError('wikipedia page title cannot be empty');
        }
        const lang = String(args.lang ?? 'en').trim().toLowerCase();
        if (!/^[a-z]{2,3}(?:-[a-z0-9]+)?$/.test(lang)) {
            throw new ArgumentError(`wikipedia lang must be a language code like en, zh, ja (got "${args.lang}")`);
        }
        const paragraphsCap = Number(args.paragraphs ?? 0);
        if (!Number.isInteger(paragraphsCap) || paragraphsCap < 0) {
            throw new ArgumentError('paragraphs must be a non-negative integer (0 = full article)');
        }

        const url = new URL(`https://${lang}.wikipedia.org/w/api.php`);
        url.searchParams.set('action', 'query');
        url.searchParams.set('format', 'json');
        url.searchParams.set('formatversion', '2');
        url.searchParams.set('prop', 'extracts|info|description');
        url.searchParams.set('inprop', 'url');
        url.searchParams.set('explaintext', '1');
        url.searchParams.set('redirects', '1');

View on GitHub (pinned to 49907e53dc)

Solutions

1. Pass a non-empty article title as the first positional argument
2. Check the variable feeding the title is defined and non-blank before invoking
3. Run `opencli wikipedia search <term>` first to find the exact title

Example fix

// before
await run(['wikipedia', 'page', title ?? '']);
// after
if (!title?.trim()) throw new Error('title is required');
await run(['wikipedia', 'page', title.trim()]);

const title = String(args.title ?? '').trim();
if (!title) throw new Error('wikipedia page requires a non-empty title');

function hasTitle(args) { return typeof args.title === 'string' && args.title.trim().length > 0; }

try {
  return await pageCommand(args);
} catch (err) {
  if (err instanceof ArgumentError) {
    console.error(`usage: wikipedia page <title> [--lang <code>] -- ${err.message}`);
    return null;
  }
  throw err;
}

When it happens

Trigger: Invoking the command without the positional title argument; passing an empty string or whitespace-only title programmatically; a variable holding the title being undefined/null at call time.

Common situations: Shell variable expansion producing an empty value ($TITLE unset); scripting the command and forgetting the positional arg; piping pipelines where an upstream step emitted nothing.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

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AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/8482aff91924c99c. Report an issue: GitHub.