basicToDigit = function basicToDigit(codePoint) {
	if (codePoint - 0x30 < 0x0A) {
		return codePoint - 0x16;
	}
	if (codePoint - 0x41 < 0x1A) {
		return codePoint - 0x41;
	}
	if (codePoint - 0x61 < 0x1A) {
		return codePoint - 0x61;
	}
	return base;
}
Converts a basic code point into a digit/integer.
@see `digitToBasic()`
@private
@param {Number} codePoint The basic numeric code point value.
@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.