function basicToDigit(codePoint) {
		return codePoint - 48 < 10
			? codePoint - 22
			: codePoint - 65 < 26
				? codePoint - 65
				: codePoint - 97 < 26
					? codePoint - 97
					: base;
	}
Converts a basic code point into a digit/integer.
@see `digitToBasic()`
@private
@param {Number} codePoint The basic (decimal) code point.
@returns {Number} The numeric value of a basic code point (for use in
representing integers) in the range `0` to `base - 1`, or `base` if
the code point does not represent a value.