code: function tryConsumeDeclare() {
              var token = scanner.getToken();
              if (token === 122 /* DeclareKeyword */) {
                  // declare module "mod"
                  token = nextToken();
                  if (token === 125 /* ModuleKeyword */) {
                      token = nextToken();
                      if (token === 9 /* StringLiteral */) {
                          recordAmbientExternalModule();
                      }
                  }
                  return true;
              }
              return false;
          }
docs: Returns true if at least one token was consumed from the stream