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crayoncode
crayoncode

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Iterative nested object traversal

Recently I had this problem where I needed to traverse deeply nested objects. More specifically it was about translation files which were of irregular structure (as usual) and partially quite deep (in some spots > 10 levels). So I needed an easy way to traverse through the entire structure and do some transformations / replacements. E.g. convert UPPERCASE to lowercase or replace language-specific quotation marks („“ «», the ones word processors like MS Word write for different languages like German or French) with ASCII quotation marks.

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Now, there's the choice of implementing the traversal algorithm recursively or iteratively. Slightly above 10 levels of recursion are unlikely to cause a stack overflow, but I wanted it to be iterative, since in my opinion it's easier to debug.

The key to the iterative implementation is to use a while loop which is kept running as long as the queue of unprocessed objects is not empty. Each object's properties are iterated and if a property contains another object it's simply enqueued to the queue. For any other kind of value a callback is called, where any kind of transformation/replacement can be made.

So, here's the code. If you want to see how it's being written, watch the video. 👋 Any feedback will be appreciated, just let me know and leave a comment. 🙏

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