Function computeCodePoint

contributes/src/vs/base/common/strings.ts:470–472

(highSurrogate: number, lowSurrogate: number)

 * See http://en.wikipedia.org/wiki/Surrogate_pair
 */
export function computeCodePoint(highSurrogate: number, lowSurrogate: number): number {
	return ((highSurrogate - 0xD800) << 10) + (lowSurrogate - 0xDC00) + 0x10000;
}

/**
 * get the code point that begins at offset `offset`