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How to sort the keys of your JSON using Codable

Paul Hudson       @twostraws

When you use JSONEncoder and Codable to create JSON from your Swift data, your properties get written out in the order they appear inside your class. This is nearly always fine, because relying on key ordering in your JSON is almost certainly a bad idea.

However, if you’re debugging a large type and it’s hard to dig through keys to find what you want, JSONEncoder has the perfect option for you: you can sort your JSON keys alphabetically.

To make it happen, change the outputFormatting property of your JSONEncoder object to be .sortedKeys, like this:

let encoder = JSONEncoder()
encoder.outputFormatting = .sortedKeys

Now any JSON you produce will use alphabetical order for your keys rather than using their natural order inside your type.

Available from iOS 8.0

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