code: function checkStrictModeIdentifier(node) {
              if (inStrictMode &&
                  node.originalKeywordKind >= 106 /* FirstFutureReservedWord */ &&
                  node.originalKeywordKind <= 114 /* LastFutureReservedWord */ &&
                  !ts.isIdentifierName(node) &&
                  !ts.isInAmbientContext(node)) {
                  // Report error only if there are no parse errors in file
                  if (!file.parseDiagnostics.length) {
                      file.bindDiagnostics.push(ts.createDiagnosticForNode(node, getStrictModeIdentifierMessage(node), ts.declarationNameToString(node)));
                  }
              }
          }
docs: The binder visits every node in the syntax tree so it is a convenient place to perform a single localized check for reserved words used as identifiers in strict mode code.