Function createScanner

src/vs/base/common/json.ts:201–559

(text: string, ignoreTrivia: boolean = false)

 * If ignoreTrivia is set, whitespaces or comments are ignored.
 */
export function createScanner(text: string, ignoreTrivia: boolean = false): JSONScanner {

	let pos = 0;
	const len = text.length;
	let value: string = '';
	let tokenOffset = 0;
	let token: SyntaxKind = SyntaxKind.Unknown;
	let scanError: ScanError = ScanError.None;

	function scanHexDigits(count: number): number {
		let digits = 0;
		let hexValue = 0;
		while (digits < count) {
			const ch = text.charCodeAt(pos);
			if (ch >= CharacterCodes._0 && ch <= CharacterCodes._9) {
				hexValue = hexValue * 16 + ch - CharacterCodes._0;
			}
			else if (ch >= CharacterCodes.A && ch <= CharacterCodes.F) {
				hexValue = hexValue * 16 + ch - CharacterCodes.A + 10;
			}
			else if (ch >= CharacterCodes.a && ch <= CharacterCodes.f) {
				hexValue = hexValue * 16 + ch - CharacterCodes.a + 10;
			}
			else {
				break;
			}
			pos++;
			digits++;
		}
		if (digits < count) {
			hexValue = -1;
		}
		return hexValue;
	}

	function setPosition(newPosition: number) {
		pos = newPosition;
		value = '';
		tokenOffset = 0;
		token = SyntaxKind.Unknown;
		scanError = ScanError.None;
	}

	function scanNumber(): string {
		const start = pos;
		if (text.charCodeAt(pos) === CharacterCodes._0) {
			pos++;
		} else {
			pos++;
			while (pos < text.length && isDigit(text.charCodeAt(pos))) {
				pos++;
			}
		}
		if (pos < text.length && text.charCodeAt(pos) === CharacterCodes.dot) {
			pos++;
			if (pos < text.length && isDigit(text.charCodeAt(pos))) {
				pos++;
				while (pos < text.length && isDigit(text.charCodeAt(pos))) {