Function visit

src/vs/base/common/json.ts:1069–1309

(text: string, visitor: JSONVisitor, options: ParseOptions = ParseOptions.DEFAULT)

 * Parses the given text and invokes the visitor functions for each object, array and literal reached.
 */
export function visit(text: string, visitor: JSONVisitor, options: ParseOptions = ParseOptions.DEFAULT): any {

	const _scanner = createScanner(text, false);

	function toNoArgVisit(visitFunction?: (offset: number, length: number) => void): () => void {
		return visitFunction ? () => visitFunction(_scanner.getTokenOffset(), _scanner.getTokenLength()) : () => true;
	}
	function toOneArgVisit<T>(visitFunction?: (arg: T, offset: number, length: number) => void): (arg: T) => void {
		return visitFunction ? (arg: T) => visitFunction(arg, _scanner.getTokenOffset(), _scanner.getTokenLength()) : () => true;
	}

	const onObjectBegin = toNoArgVisit(visitor.onObjectBegin),
		onObjectProperty = toOneArgVisit(visitor.onObjectProperty),
		onObjectEnd = toNoArgVisit(visitor.onObjectEnd),
		onArrayBegin = toNoArgVisit(visitor.onArrayBegin),
		onArrayEnd = toNoArgVisit(visitor.onArrayEnd),
		onLiteralValue = toOneArgVisit(visitor.onLiteralValue),
		onSeparator = toOneArgVisit(visitor.onSeparator),
		onComment = toNoArgVisit(visitor.onComment),
		onError = toOneArgVisit(visitor.onError);

	const disallowComments = options && options.disallowComments;
	const allowTrailingComma = options && options.allowTrailingComma;
	function scanNext(): SyntaxKind {
		while (true) {
			const token = _scanner.scan();
			switch (_scanner.getTokenError()) {
				case ScanError.InvalidUnicode:
					handleError(ParseErrorCode.InvalidUnicode);
					break;
				case ScanError.InvalidEscapeCharacter:
					handleError(ParseErrorCode.InvalidEscapeCharacter);
					break;
				case ScanError.UnexpectedEndOfNumber:
					handleError(ParseErrorCode.UnexpectedEndOfNumber);
					break;
				case ScanError.UnexpectedEndOfComment:
					if (!disallowComments) {
						handleError(ParseErrorCode.UnexpectedEndOfComment);
					}
					break;
				case ScanError.UnexpectedEndOfString:
					handleError(ParseErrorCode.UnexpectedEndOfString);
					break;
				case ScanError.InvalidCharacter:
					handleError(ParseErrorCode.InvalidCharacter);
					break;
			}
			switch (token) {
				case SyntaxKind.LineCommentTrivia:
				case SyntaxKind.BlockCommentTrivia:
					if (disallowComments) {
						handleError(ParseErrorCode.InvalidCommentToken);
					} else {
						onComment();
					}
					break;
				case SyntaxKind.Unknown: