Check if a string contains only letters and numbers

Test for one or more ASCII letters or digits.

JavaScript Version 1.0.0 · MIT · .md

function isAlphanumeric(text) { return /^[0-9A-Z]+$/i.test(text); }

Input & expected output

"Order8812"

true

The edge case

"Order 8812"

false

Know the limits

• ASCII only: accented letters and spaces fail. The empty string fails too.

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.