What causes "A provider and page loader are required." in Hmbown/CodeWhale?

Pass a non-empty provider id string as the first argument.

A provider and page loader are required.

Error message

A provider and page loader are required.

What it means

collectProviderModelPages paginates a provider's model catalog and requires a non-empty provider id plus a callable fetchPage loader. Anything else is a caller bug (it cannot know which provider's pages to fetch or how to fetch them), so it throws up front.

Solutions

Pass a non-empty provider id string as the first argument.
Pass the actual page-loader function (e.g. (url) => fetch(url).then(r => r.json())) as the second argument.
Check the import of the loader function if it comes from another module (name typo yields undefined).

Example fix

// before
const models = await collectProviderModelPages(providerId, loaderUrl);
// after
const models = await collectProviderModelPages(providerId, (url) => fetch(url).then((r) => r.json()));

Defensive patterns

Strategy: validation

Validate before calling

if (providerId && typeof fetchPage === 'function') {
  const pages = await collectProviderModelPages(providerId, fetchPage);
}

Type guard

function canCollect(providerId, fetchPage) {
  return String(providerId || '').trim().length > 0 && typeof fetchPage === 'function';
}

Try / catch

try {
  const pages = await collectProviderModelPages(providerId, fetchPage);
} catch (e) {
  console.error('collectProviderModelPages misused:', e.message);
}

Prevention

Assert loader arguments with unit tests for the pagination helper.
Import the loader by name and verify it is not undefined at call time.
Keep provider id and loader wiring together in one call site.

When it happens

Trigger: Calling collectProviderModelPages('') or with a non-function second argument (undefined when an optional dependency failed to load, or a value mistakenly passed instead of a function).

Common situations: Refactoring left the fetch callback undefined; provider id lost from scope and passed as empty string; tests or callers invoking the helper directly with wrong arity.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/b1e60a26d6c05ccc. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/runtime_web/app.mjs:653

}

const PROVIDER_MODELS_PAGE_SIZE = 250;
const MAX_PROVIDER_MODELS = 10_000;
const MAX_PROVIDER_MODEL_PAGES = Math.ceil(
  MAX_PROVIDER_MODELS / PROVIDER_MODELS_PAGE_SIZE,
);

/**
 * Load every bounded page of one provider catalog.
 *
 * `fetchPage` is injected so the browser client can retain its authenticated
 * Runtime API boundary and tests can prove catalogs larger than one page are
 * not silently truncated. Cursors are opaque and may never repeat.
 */
export async function collectProviderModelPages(providerId, fetchPage) {
  const provider = String(providerId || "").trim();
  if (!provider || typeof fetchPage !== "function") {
    throw new Error("A provider and page loader are required.");
  }

  const entries = [];
  const seenCursors = new Set();
  let expectedTotal;
  let cursor = "";
  for (let page = 0; page < MAX_PROVIDER_MODEL_PAGES; page += 1) {
    const query = new URLSearchParams({ limit: String(PROVIDER_MODELS_PAGE_SIZE) });
    if (cursor) query.set("cursor", cursor);
    const response = await fetchPage(
      `/v1/providers/${encodeURIComponent(provider)}/models?${query.toString()}`,
    );
    if (String(response?.provider || "") !== provider) {
      throw new Error("The Runtime returned a model page for a different provider.");
    }
    if (!Array.isArray(response?.models)
      || response.models.length > PROVIDER_MODELS_PAGE_SIZE
      || !Number.isSafeInteger(response.total)

View on GitHub (pinned to 73e0f67d83)