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Learning Node.js Development

You're reading from   Learning Node.js Development Learn the fundamentals of Node.js, and deploy and test Node.js applications on the web

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Product type Paperback
Published in Jan 2018
Publisher Packt
ISBN-13 9781788395540
Length 658 pages
Edition 1st Edition
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Author (1):
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Andrew Mead Andrew Mead
Author Profile Icon Andrew Mead
Andrew Mead
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Table of Contents (13) Chapters Close

Preface 1. Getting Set Up 2. Node Fundamentals – Part 1 FREE CHAPTER 3. Node Fundamentals – Part 2 4. Node Fundamentals – Part 3 5. Basics of Asynchronous Programming in Node.js 6. Callbacks in Asynchronous Programming 7. Promises in Asynchronous Programming 8. Web Servers in Node 9. Deploying Applications to Web 10. Testing the Node Applications – Part 1 11. Testing the Node Applications – Part 2 12. Another Book You May Enjoy

Callback errors

In this section we'll learn how to handle errors inside of your callback functions, because as you might guess things don't always go as planned. For example, the current version of our app has a few really big flaws, if I try to fetch weather using node app.js with the a flag for a zip that doesn't exist, like 000000, the program crashes, which is a really big problem. It's going off. It's fetching the data, eventually that data will come back and we get an error, as shown here:

It's trying to fetch properties that don't exist, such as body.results[0].formatted_address is not a real property, and this is a big problem.

Our current callback expects everything went as planned. It doesn't care about the error object, doesn't look at response codes; it just starts printing the data that it wants. This is the happy path...

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