Function parseTypePredicatePrefix

test/fixtures/snapshot/typescript.js:34257–34263

()

            }
        }
        function parseTypePredicatePrefix() {
            var id = parseIdentifier();
            if (token() === 139 /* SyntaxKind.IsKeyword */ && !scanner.hasPrecedingLineBreak()) {
                nextToken();
                return id;
            }
        }
        function parseAssertsTypePredicate() {
            var pos = getNodePos();
            var assertsModifier = parseExpectedToken(128 /* SyntaxKind.AssertsKeyword */);