Parsing JSON from Postgres in JS? Don't get the wrong number
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JavaScript's native JSON.parse() silently corrupts large integers (e.g., Postgres bigint values) by converting them to float64, losing precision without any warning. Existing npm packages like json-bigint and lossless-json address this but have conformance gaps and are 4–11× slower than native parsing. The author introduces json-custom-numbers, a new JavaScript JSON parser that fully matches native JSON.parse() behavior, supports custom number-parsing callbacks, and runs only 1.5–3× slower. The post also covers implementation lessons: sticky RegExps for performance, JavaScript engine JIT memory effects on benchmarking, non-recursive parsing via state machine, and the surprising fact that native JSON.stringify() is still recursive.
