Check if a string is a MongoDB ObjectId

Test for exactly 24 hexadecimal characters.

JavaScript Version 1.0.0 · MIT · .md

function isMongoId(text) { return /^[0-9a-f]{24}$/i.test(text); }

Input & expected output

"507f1f77bcf86cd799439011"

true

The edge case

"507f1f77bcf86cd79943901z"

false

Know the limits

• This checks the format only, not that the document exists.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Check whether all values are equal — Compare every item with the first using Object.is.
• Check whether an object is empty — Check for own enumerable string keys on a JSON object.
• Check whether an integer is even — Test parity for safe integers, including zero and negative values.