feat(eslint-plugin): [block-spacing] extending base rule for TS related blocks

packages/eslint-plugin/docs/rules/block-spacing.md

@@ -0,0 +1,12 @@
+---
+description: 'Disallow or enforce spaces inside of blocks after opening block and before closing block.'
+---
+
+> 🛑 This file is source code, not the primary documentation location! 🛑
+>
+> See **https://typescript-eslint.io/rules/block-spacing** for documentation.
+
+## Examples
+
+This rule extends the base [`eslint/block-spacing`](https://eslint.org/docs/rules/block-spacing) rule.
+This version adds support for TypeScript related blocks (interfaces, object type literals and enums).

packages/eslint-plugin/src/configs/all.ts

@@ -11,6 +11,8 @@ export = {
     '@typescript-eslint/ban-ts-comment': 'error',
     '@typescript-eslint/ban-tslint-comment': 'error',
     '@typescript-eslint/ban-types': 'error',
+    'block-spacing': 'off',
+    '@typescript-eslint/block-spacing': 'error',
     'brace-style': 'off',
     '@typescript-eslint/brace-style': 'error',
     '@typescript-eslint/class-literal-property-style': 'error',

packages/eslint-plugin/src/rules/block-spacing.ts

@@ -0,0 +1,166 @@
+import type { TSESTree } from '@typescript-eslint/utils';
+import { AST_TOKEN_TYPES } from '@typescript-eslint/utils';
+
+import * as util from '../util';
+import { getESLintCoreRule } from '../util/getESLintCoreRule';
+
+const baseRule = getESLintCoreRule('block-spacing');
+
+export type Options = util.InferOptionsTypeFromRule<typeof baseRule>;
+export type MessageIds = util.InferMessageIdsTypeFromRule<typeof baseRule>;
+
+export default util.createRule<Options, MessageIds>({
+  name: 'block-spacing',
+  meta: {
+    type: 'layout',
+    docs: {
+      description:
+        'Disallow or enforce spaces inside of blocks after opening block and before closing block',
+      recommended: false,
+      extendsBaseRule: true,
+    },
+    fixable: 'whitespace',
+    hasSuggestions: baseRule.meta.hasSuggestions,
+    schema: baseRule.meta.schema,
+    messages: baseRule.meta.messages,
+  },
+  defaultOptions: ['always'],
+
+  create(context, [whenToApplyOption]) {
+    const sourceCode = context.getSourceCode();
+    const baseRules = baseRule.create(context);
+    const always = whenToApplyOption !== 'never';
+    const messageId = always ? 'missing' : 'extra';
+    /**
+     * Gets the open brace token from a given node.
+     * @returns The token of the open brace.
+     */
+    function getOpenBrace(
+      node: TSESTree.TSEnumDeclaration,
+    ): TSESTree.PunctuatorToken {
+      // guaranteed for enums
+      // This is the only change made here from the base rule
+      return sourceCode.getFirstToken(node, {
+        filter: token =>
+          token.type === AST_TOKEN_TYPES.Punctuator && token.value == '{',
+      }) as TSESTree.PunctuatorToken;
+    }
+
+    /**
+     * Checks whether or not:
+     *   - given tokens are on same line.
+     *   - there is/isn't a space between given tokens.
+     * @param left A token to check.
+     * @param right The token which is next to `left`.
+     * @returns
+     *    When the option is `"always"`, `true` if there are one or more spaces between given tokens.
+     *    When the option is `"never"`, `true` if there are not any spaces between given tokens.
+     *    If given tokens are not on same line, it's always `true`.
+     */
+    function isValid(left: TSESTree.Token, right: TSESTree.Token): boolean {
+      return (
+        !util.isTokenOnSameLine(left, right) ||
+        sourceCode.isSpaceBetween!(left, right) === always
+      );
+    }
+
+    /**
+     * Checks and reports invalid spacing style inside braces.
+     * @param {ASTNode} node A BlockStatement/StaticBlock/SwitchStatement node to check.
+     * @returns
+     */
+    function checkSpacingInsideBraces(node: TSESTree.TSEnumDeclaration): void {
+      // 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 !== AST_TOKEN_TYPES.Punctuator ||
+        openBrace.value !== '{' ||
+        closeBrace.type !== AST_TOKEN_TYPES.Punctuator ||
+        closeBrace.value !== '}' ||
+        firstToken === closeBrace
+      ) {
+        return;
+      }
+
+      // Skip line comments for option never
+      if (!always && firstToken.type === AST_TOKEN_TYPES.Line) {
+        return;
+      }
+
+      // Check.
+      if (!isValid(openBrace, firstToken)) {
+        let loc = openBrace.loc;
+
+        if (messageId === 'extra') {
+          loc = {
+            start: openBrace.loc.end,
+            end: firstToken.loc.start,
+          };
+        }
+
+        context.report({
+          node,
+          loc,
+          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)) {
+        let loc = closeBrace.loc;
+
+        if (messageId === 'extra') {
+          loc = {
+            start: lastToken.loc.end,
+            end: closeBrace.loc.start,
+          };
+        }
+        context.report({
+          node,
+          loc,
+          messageId,
+          data: {
+            location: 'before',
+            token: closeBrace.value,
+          },
+          fix(fixer) {
+            if (always) {
+              return fixer.insertTextAfter(lastToken, ' ');
+            }
+
+            return fixer.removeRange([lastToken.range[1], closeBrace.range[0]]);
+          },
+        });
+      }
+    }
+    return {
+      ...baseRules,
+
+      // This code worked "out of the box" for interface and type literal
+      // Enums were very close to match as well, the only reason they it not is that was that enums don't have a body node in the parser
+      // So the opening brace punctuator starts in the middle of the node
+      // `getFirstToken` in the base rule did not filter for the first opening brace punctuator
+      TSInterfaceBody: baseRules.BlockStatement as never,
+      TSTypeLiteral: baseRules.BlockStatement as never,
+      TSEnumDeclaration: checkSpacingInsideBraces,
+    };
+  },
+});

packages/eslint-plugin/src/rules/index.ts

@@ -4,6 +4,7 @@ import awaitThenable from './await-thenable';
 import banTsComment from './ban-ts-comment';
 import banTslintComment from './ban-tslint-comment';
 import banTypes from './ban-types';
+import blockSpacing from './block-spacing';
 import braceStyle from './brace-style';
 import classLiteralPropertyStyle from './class-literal-property-style';
 import commaDangle from './comma-dangle';
@@ -135,6 +136,7 @@ export default {
   'ban-ts-comment': banTsComment,
   'ban-tslint-comment': banTslintComment,
   'ban-types': banTypes,
+  'block-spacing': blockSpacing,
   'brace-style': braceStyle,
   'class-literal-property-style': classLiteralPropertyStyle,
   'comma-dangle': commaDangle,

packages/eslint-plugin/src/util/getESLintCoreRule.ts

@@ -7,6 +7,7 @@ const isESLintV8 = semver.major(version) >= 8;
 interface RuleMap {
   /* eslint-disable @typescript-eslint/consistent-type-imports -- more concise to use inline imports */
   'arrow-parens': typeof import('eslint/lib/rules/arrow-parens');
+  'block-spacing': typeof import('eslint/lib/rules/block-spacing');
   'brace-style': typeof import('eslint/lib/rules/brace-style');
   'comma-dangle': typeof import('eslint/lib/rules/comma-dangle');
   'dot-notation': typeof import('eslint/lib/rules/dot-notation');

packages/eslint-plugin/tests/rules/block-spacing.test.ts

@@ -0,0 +1,92 @@
+import { AST_NODE_TYPES } from '@typescript-eslint/utils';
+
+import rule from '../../src/rules/block-spacing';
+import type { InvalidTestCase, ValidTestCase } from '../RuleTester';
+import { RuleTester } from '../RuleTester';
+
+const ruleTester = new RuleTester({
+  parser: '@typescript-eslint/parser',
+});
+
+type InvalidBlockSpacingTestCase = InvalidTestCase<
+  'missing' | 'extra',
+  ['always' | 'never']
+>;
+
+const options = ['always', 'never'] as const;
+const typeDeclaration = [
+  {
+    nodeType: AST_NODE_TYPES.TSInterfaceBody,
+    stringPrefix: 'interface Foo ',
+  },
+  {
+    nodeType: AST_NODE_TYPES.TSTypeLiteral,
+    stringPrefix: 'type Foo = ',
+  },
+  {
+    nodeType: AST_NODE_TYPES.TSEnumDeclaration,
+    stringPrefix: 'enum Foo ',
+  },
+  {
+    nodeType: AST_NODE_TYPES.TSEnumDeclaration,
+    stringPrefix: 'const enum Foo ',
+  },
+];
+const emptyBlocks = ['{}', '{ }'];
+const singlePropertyBlocks = ['{bar: true}', '{ bar: true }'];
+
+ruleTester.run('block-spacing', rule, {
+  valid: [
+    // Empty blocks don't apply
+    ...options.flatMap(option =>
+      typeDeclaration.flatMap(typeDec =>
+        emptyBlocks.map<ValidTestCase<['always' | 'never']>>(blockType => ({
+          code: typeDec.stringPrefix + blockType,
+          options: [option],
+        })),
+      ),
+    ),
+  ],
+  invalid: [
+    ...options.flatMap(option =>
+      typeDeclaration.flatMap(typeDec => {
+        return singlePropertyBlocks.flatMap<InvalidBlockSpacingTestCase>(
+          (blockType, blockIndex) => {
+            // These are actually valid, so filter them out
+            if (
+              (option === 'always' && blockType.startsWith('{ ')) ||
+              (option === 'never' && blockType.startsWith('{bar'))
+            ) {
+              return [];
+            }
+            const reverseBlockType = singlePropertyBlocks[1 - blockIndex];
+            let code = `${typeDec.stringPrefix}${blockType};  /* ${option} */`;
+            let output = `${typeDec.stringPrefix}${reverseBlockType};  /* ${option} */`;
+            if (typeDec.nodeType === AST_NODE_TYPES.TSEnumDeclaration) {
+              output = output.replace(':', '=');
+              code = code.replace(':', '=');
+            }
+
+            return {
+              code,
+              options: [option],
+              output,
+              errors: [
+                {
+                  type: typeDec.nodeType,
+                  messageId: option === 'always' ? 'missing' : 'extra',
+                  data: { location: 'after', token: '{' },
+                },
+                {
+                  type: typeDec.nodeType,
+                  messageId: option === 'always' ? 'missing' : 'extra',
+                  data: { location: 'before', token: '}' },
+                },
+              ],
+            };
+          },
+        );
+      }),
+    ),
+  ],
+});

packages/eslint-plugin/typings/eslint-rules.d.ts

@@ -609,6 +609,21 @@ declare module 'eslint/lib/rules/quotes' {
   export = rule;
 }
 
+declare module 'eslint/lib/rules/block-spacing' {
+  import type { TSESLint, TSESTree } from '@typescript-eslint/utils';
+
+  const rule: TSESLint.RuleModule<
+    'missing' | 'extra',
+    ['always' | 'never'],
+    {
+      BlockStatement(node: TSESTree.BlockStatement): void;
+      StaticBlock(node: TSESTree.StaticBlock): void;
+      SwitchStatement(node: TSESTree.SwitchStatement): void;
+    }
+  >;
+  export = rule;
+}
+
 declare module 'eslint/lib/rules/brace-style' {
   import type { TSESLint, TSESTree } from '@typescript-eslint/utils';