Check if a string contains upper case characters

Compare a string with its lowercase form.

JavaScript Version 1.0.0 · MIT · .md

function containsUpperCase(text) { return text !== text.toLowerCase(); }

Input & expected output

"Order 8812"

true

The edge case

"8812"

false

Know the limits

• Any cased letter counts, in any script. Digits and symbols never do.

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.