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Practical tutorials for the work we actually do. Pick one, read it in order, and apply it.

Any category Programming12 Python 2 JavaScript 5 TypeScript 5
Any topics APIs and Integrations 5 Automation and Scripting 1 Data Structures and Algorithms 2 Object-Oriented Programming 3 Packaging and Dependencies 4 Performance Optimization 6 Programming Basics 10 Programming Patterns 5 Testing and Debugging 10 Type Systems 1 Web Development 3
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JavaScript APIs and Integrations Clear filters 5 results
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fetch With Proper Error Handling (It Doesn't Throw on 404)

fetch only rejects when there's no response. A 404 or 500 resolves normally, so check response.ok, add a timeout, and keep the status on the error so the caller can decide what to tell the user.

5 min read
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Fix "Unexpected token in JSON" Errors

"Unexpected token in JSON" means JSON.parse got text that isn't JSON. Read the exact message, log the raw text, and match it to one of five causes. Most of the time it's an HTML error or login page.

5 min read
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Batch API Calls With Promise.allSettled

Send many requests, keep the successes, and report the failures instead of losing everything to one rejected promise. Plus limiting how many run at once.

4 min read
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Add a Timeout to fetch With AbortController

fetch has no timeout option and can wait a very long time. AbortSignal.timeout(ms) fixes that in one line, and AbortSignal.any combines it with a cancel button.

4 min read
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Paginate an API With an Async Generator

Hide page numbers and "next" links inside an async generator, then loop over every record with for await. Stop early and the remaining pages are never fetched.

4 min read