Verified Developer Solution • 100% OfflineFix "TypeError: Data must be a string or a buffer"
Resolve hashing crashes when passing objects or numbers into crypto update functions.
The Problem (Error Root Cause)Exception
When calling `hash.update(data)`, you receive a TypeError. This occurs because hashing algorithms only operate on raw bytes (strings or buffers), but you passed an object, array, or number.
Identified via runtime validation & stack traces
The Solution (Step-by-Step Fix)Verified
Stringify the object or cast the number to a string before hashing it.
Deterministic, non-destructive resolution
Code Standard: Bad Pattern vs Verified Fix
Live SyntaxAnti-Pattern vs Verified Fix
1// ❌ Bad: Passing an object2const data = { id: 1 };3crypto.createHash('sha256').update(data);4 5// ✅ Good: Stringify first6const data = { id: 1 };7crypto.createHash('sha256').update(JSON.stringify(data));Test and resolve this using Hash Generator (MD5, SHA256, SHA512)
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Frequently Asked Questions
Q:Will JSON.stringify produce the same hash every time?
Only if the key order is strictly identical. For deterministic hashing of objects, use a library like json-stable-stringify.
Q:Where can I quickly test hashes?
Our Hash Generator allows you to paste raw text and get instant cryptographic outputs.