code: function checkSpacingInsideBraces(node) {
  
              // Gets braces and the first/last token of content.
              const openBrace = getOpenBrace(node);
              const closeBrace = sourceCode.getLastToken(node);
              const firstToken = sourceCode.getTokenAfter(openBrace, { includeComments: true });
              const lastToken = sourceCode.getTokenBefore(closeBrace, { includeComments: true });
  
              // Skip if the node is invalid or empty.
              if (openBrace.type !== "Punctuator" ||
                  openBrace.value !== "{" ||
                  closeBrace.type !== "Punctuator" ||
                  closeBrace.value !== "}" ||
                  firstToken === closeBrace
              ) {
                  return;
              }
  
              // Skip line comments for option never
              if (!always && firstToken.type === "Line") {
                  return;
              }
  
              // Check.
              if (!isValid(openBrace, firstToken)) {
                  context.report({
                      node,
                      loc: openBrace.loc.start,
                      messageId,
                      data: {
                          location: "after",
                          token: openBrace.value
                      },
                      fix(fixer) {
                          if (always) {
                              return fixer.insertTextBefore(firstToken, " ");
                          }
  
                          return fixer.removeRange([openBrace.range[1], firstToken.range[0]]);
                      }
                  });
              }
              if (!isValid(lastToken, closeBrace)) {
                  context.report({
                      node,
                      loc: closeBrace.loc.start,
                      messageId,
                      data: {
                          location: "before",
                          token: closeBrace.value
                      },
                      fix(fixer) {
                          if (always) {
                              return fixer.insertTextAfter(lastToken, " ");
                          }
  
                          return fixer.removeRange([lastToken.range[1], closeBrace.range[0]]);
                      }
                  });
              }
          }
docs: Reports invalid spacing style inside braces.
  @param {ASTNode} node - A BlockStatement/SwitchStatement node to get.
  @returns {void}