JSON replacer in JavaScript

What this snippet does

The replacer filters what gets serialized; the reviver transforms values back — use it to restore Dates, Maps, or sensitive-field stripping.

Expected output

{"name":"Alice","age":30}
true

Why practise typing this

Typing json code builds muscle memory for the symbols and indentation JavaScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.

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