javascript 24 lines · 6 steps

Cursor-based pagination with fetch

An async loop walks every page of a cursor-paginated API and collects all rows into one array.

Explained by highlit
Intermediate pagination async-await fetch cursors error-handling
1async function fetchAllPages(baseUrl, { pageSize = 100, headers = {} } = {}) {
2 const results = [];
3 let cursor = null;
4 
5 do {
6 const url = new URL(baseUrl);
7 url.searchParams.set('limit', String(pageSize));
8 if (cursor) url.searchParams.set('cursor', cursor);
9 
10 const res = await fetch(url, {
11 headers: { Accept: 'application/json', ...headers },
12 });
13 
14 if (!res.ok) {
15 throw new Error(`Request failed: ${res.status} ${res.statusText}`);
16 }
17 
18 const { data, next_cursor: nextCursor } = await res.json();
19 results.push(...data);
20 cursor = nextCursor ?? null;
21 } while (cursor);
22 
23 return results;
24}
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STEP 01

Walkthrough

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Three takeaways
  1. 1A do/while loop is ideal for pagination since you always need at least one request before knowing if more pages exist.
  2. 2Cursor pagination chains requests by feeding each response's next cursor into the following call until it runs dry.
  3. 3Building a URL with URLSearchParams keeps query parameters safely encoded and conditional ones easy to add.

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