typescript-eslint · bradzacher · Apr 29, 2020 · Apr 28, 2020 · Apr 28, 2020 · Apr 29, 2020
diff --git a/packages/eslint-plugin-internal/src/rules/index.ts b/packages/eslint-plugin-internal/src/rules/index.ts
@@ -1,9 +1,11 @@
+import noPoorlyTypedTsProps from './no-poorly-typed-ts-props';
 import noTypescriptDefaultImport from './no-typescript-default-import';
 import noTypescriptEstreeImport from './no-typescript-estree-import';
 import pluginTestFormatting from './plugin-test-formatting';
 import preferASTTypesEnum from './prefer-ast-types-enum';
 
 export default {
+  'no-poorly-typed-ts-props': noPoorlyTypedTsProps,
   'no-typescript-default-import': noTypescriptDefaultImport,
   'no-typescript-estree-import': noTypescriptEstreeImport,
   'plugin-test-formatting': pluginTestFormatting,

diff --git a/packages/eslint-plugin-internal/src/rules/no-poorly-typed-ts-props.ts b/packages/eslint-plugin-internal/src/rules/no-poorly-typed-ts-props.ts
@@ -0,0 +1,110 @@
+import {
+  TSESTree,
+  ESLintUtils,
+  TSESLint,
+} from '@typescript-eslint/experimental-utils';
+import { createRule } from '../util';
+
+/*
+TypeScript declares some bad types for certain properties.
+See: https://github.com/microsoft/TypeScript/issues/24706
+
+This rule simply warns against using them, as using them will likely introduce type safety holes.
+*/
+
+const BANNED_PROPERTIES = [
+  // {
+  //   type: 'Node',
+  //   property: 'parent',
+  //   fixWith: null,
+  // },
+  {
+    type: 'Symbol',
+    property: 'declarations',
+    fixWith: 'getDeclarations()',
+  },
+  {
+    type: 'Type',
+    property: 'symbol',
+    fixWith: 'getSymbol()',
+  },
+];
+
+export default createRule({
+  name: 'no-poorly-typed-ts-props',
+  meta: {
+    type: 'problem',
+    docs: {
+      description:
+        "Enforces rules don't use TS API properties with known bad type definitions",
+      category: 'Possible Errors',
+      recommended: 'error',
+      requiresTypeChecking: true,
+    },
+    fixable: 'code',
+    schema: [],
+    messages: {
+      doNotUse: 'Do not use {{type}}.{{property}} because it is poorly typed.',
+      doNotUseWithFixer:
+        'Do not use {{type}}.{{property}} because it is poorly typed. Use {{type}}.{{fixWith}} instead.',
+      suggestedFix: 'Use {{type}}.{{fixWith}} instead.',
+    },
+  },
+  defaultOptions: [],
+  create(context) {
+    const { program, esTreeNodeToTSNodeMap } = ESLintUtils.getParserServices(
+      context,
+    );
+    const checker = program.getTypeChecker();
+
+    return {
+      ':matches(MemberExpression, OptionalMemberExpression)[computed = false]'(
+        node:
+          | TSESTree.MemberExpressionNonComputedName
+          | TSESTree.OptionalMemberExpressionNonComputedName,
+      ): void {
+        for (const banned of BANNED_PROPERTIES) {
+          if (node.property.name !== banned.property) {
+            continue;
+          }
+
+          // make sure the type name matches
+          const tsObjectNode = esTreeNodeToTSNodeMap.get(node.object);
+          const objectType = checker.getTypeAtLocation(tsObjectNode);
+          const objectSymbol = objectType.getSymbol();
+          if (objectSymbol?.getName() !== banned.type) {
+            continue;
+          }
+
+          const tsNode = esTreeNodeToTSNodeMap.get(node.property);
+          const symbol = checker.getSymbolAtLocation(tsNode);
+          const decls = symbol?.getDeclarations();
+          const isFromTs = decls?.some(decl =>
+            decl.getSourceFile().fileName.includes('/node_modules/typescript/'),
+          );
+          if (isFromTs !== true) {
+            continue;
+          }
+
+          return context.report({
+            node,
+            messageId: banned.fixWith ? 'doNotUseWithFixer' : 'doNotUse',
+            data: banned,
+            suggest: [
+              {
+                messageId: 'suggestedFix',
+                fix(fixer): TSESLint.RuleFix | null {
+                  if (banned.fixWith == null) {
+                    return null;
+                  }
+
+                  return fixer.replaceText(node.property, banned.fixWith);
+                },
+              },
+            ],
+          });
+        }
+      },
+    };
+  },
+});
diff --git a/packages/eslint-plugin-internal/tests/fixtures/file.ts b/packages/eslint-plugin-internal/tests/fixtures/file.ts
diff --git a/packages/eslint-plugin-internal/tests/fixtures/tsconfig.json b/packages/eslint-plugin-internal/tests/fixtures/tsconfig.json
@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "jsx": "preserve",
+    "target": "es5",
+    "module": "commonjs",
+    "strict": true,
+    "esModuleInterop": true,
+    "lib": ["es2015", "es2017", "esnext"],
+    "experimentalDecorators": true
+  },
+  "include": ["file.ts"]
+}
diff --git a/packages/eslint-plugin-internal/tests/rules/no-poorly-typed-ts-props.test.ts b/packages/eslint-plugin-internal/tests/rules/no-poorly-typed-ts-props.test.ts
@@ -0,0 +1,94 @@
+import rule from '../../src/rules/no-poorly-typed-ts-props';
+import { RuleTester, getFixturesRootDir } from '../RuleTester';
+
+const ruleTester = new RuleTester({
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: './tsconfig.json',
+    tsconfigRootDir: getFixturesRootDir(),
+    sourceType: 'module',
+  },
+});
+
+ruleTester.run('no-poorly-typed-ts-props', rule, {
+  valid: [
+    `
+declare const foo: { declarations: string[] };
+foo.declarations.map(decl => console.log(decl));
+    `,
+    `
+declare const bar: Symbol;
+bar.declarations.map(decl => console.log(decl));
+    `,
+    `
+declare const baz: Type;
+baz.symbol.name;
+    `,
+  ],
+  invalid: [
+    {
+      code: `
+import ts from 'typescript';
+declare const thing: ts.Symbol;
+thing.declarations.map(decl => {});
+      `.trimRight(),
+      errors: [
+        {
+          messageId: 'doNotUseWithFixer',
+          data: {
+            type: 'Symbol',
+            property: 'declarations',
+            fixWith: 'getDeclarations()',
+          },
+          line: 4,
+          suggestions: [
+            {
+              messageId: 'suggestedFix',
+              data: {
+                type: 'Symbol',
+                fixWith: 'getDeclarations()',
+              },
+              output: `
+import ts from 'typescript';
+declare const thing: ts.Symbol;
+thing.getDeclarations().map(decl => {});
+              `.trimRight(),
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: `
+import ts from 'typescript';
+declare const thing: ts.Type;
+thing.symbol;
+      `.trimRight(),
+      errors: [
+        {
+          messageId: 'doNotUseWithFixer',
+          data: {
+            type: 'Type',
+            property: 'symbol',
+            fixWith: 'getSymbol()',
+          },
+          line: 4,
+          suggestions: [
+            {
+              messageId: 'suggestedFix',
+              data: {
+                type: 'Type',
+                fixWith: 'getSymbol()',
+              },
+              output: `
+import ts from 'typescript';
+declare const thing: ts.Type;
+thing.getSymbol();
+              `.trimRight(),
+            },
+          ],
+        },
+      ],
+    },
+  ],
+});