--- /dev/null
+'use strict'
+
+module.exports = hexadecimal
+
+// Check if the given character code, or the character code at the first
+// character, is hexadecimal.
+function hexadecimal(character) {
+ var code = typeof character === 'string' ? character.charCodeAt(0) : character
+
+ return (
+ (code >= 97 /* a */ && code <= 102) /* z */ ||
+ (code >= 65 /* A */ && code <= 70) /* Z */ ||
+ (code >= 48 /* A */ && code <= 57) /* Z */
+ )
+}