javascript / intermediate
Snippet
Custom Async Iterators for API Pagination
Async generators allow you to create custom iterators that produce values asynchronously. Using yield* with an array inside the loop allows you to flatten the paginated results, providing a seamless for-await-of loop for the consumer of the data.
snippet.js
javascript
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async function* fetchUserPages(baseUrl) {let page = 1;while (true) {const response = await fetch(`${baseUrl}?page=${page}`);const data = await response.json();if (data.users.length === 0) break;yield* data.users;page++;}}// Usage:for await (const user of fetchUserPages('https://api.example.com/v1')) {console.log(user.name);}
nodejs
Breakdown
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async function* fetchUserPages(baseUrl)
Defines an asynchronous generator function.
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yield* data.users;
Delegates iteration to each individual element of the fetched users array.