typescript-eslint · bradzacher · Jan 25, 2020 · Jan 24, 2020 · Jan 24, 2020 · Jan 24, 2020
diff --git a/packages/eslint-plugin-internal/src/rules/index.ts b/packages/eslint-plugin-internal/src/rules/index.ts
@@ -1,7 +1,9 @@
 import noTypescriptDefaultImport from './no-typescript-default-import';
 import noTypescriptEstreeImport from './no-typescript-estree-import';
+import preferASTTypesEnum from './prefer-ast-types-enum';
 
 export default {
   'no-typescript-default-import': noTypescriptDefaultImport,
   'no-typescript-estree-import': noTypescriptEstreeImport,
+  'prefer-ast-types-enum': preferASTTypesEnum,
 };
diff --git a/packages/eslint-plugin-internal/src/rules/prefer-ast-types-enum.ts b/packages/eslint-plugin-internal/src/rules/prefer-ast-types-enum.ts
@@ -0,0 +1,70 @@
+import {
+  AST_NODE_TYPES,
+  AST_TOKEN_TYPES,
+  ESLintUtils,
+  TSESTree,
+} from '@typescript-eslint/experimental-utils';
+
+const isStringLiteral = (
+  node: TSESTree.Literal,
+): node is TSESTree.StringLiteral => typeof node.value === 'string';
+
+export = ESLintUtils.RuleCreator(name => name)({
+  name: __filename,
+  meta: {
+    type: 'problem',
+    docs: {
+      category: 'Best Practices',
+      recommended: 'error',
+      description:
+        'Ensures consistent usage of AST_NODE_TYPES & AST_TOKEN_TYPES enums.',
+    },
+    messages: {
+      preferEnum: 'Prefer {{ enumName }}.{{ literal }} over raw literal',
+    },
+    fixable: 'code',
+    schema: [],
+  },
+  defaultOptions: [],
+  create(context) {
+    const report = (
+      enumName: 'AST_NODE_TYPES' | 'AST_TOKEN_TYPES',
+      literal: TSESTree.StringLiteral,
+    ): void =>
+      context.report({
+        data: { enumName, literal: literal.value },
+        messageId: 'preferEnum',
+        node: literal,
+        fix: fixer =>
+          fixer.replaceText(literal, `${enumName}.${literal.value}`),
+      });
+
+    return {
+      Literal(node: TSESTree.Literal): void {
+        if (
+          node.parent?.type === AST_NODE_TYPES.TSEnumMember &&
+          node.parent.parent?.type === AST_NODE_TYPES.TSEnumDeclaration &&
+          ['AST_NODE_TYPES', 'AST_TOKEN_TYPES'].includes(
+            node.parent.parent.id.name,
+          )
+        ) {
+          return;
+        }
+
+        if (!isStringLiteral(node)) {
+          return;
+        }
+
+        const value = node.value;
+
+        if (Object.prototype.hasOwnProperty.call(AST_NODE_TYPES, value)) {
+          report('AST_NODE_TYPES', node);
+        }
+
+        if (Object.prototype.hasOwnProperty.call(AST_TOKEN_TYPES, value)) {
+          report('AST_TOKEN_TYPES', node);
+        }
+      },
+    };
+  },
+});
diff --git a/packages/eslint-plugin-internal/tests/rules/prefer-ast-types-enum.test.ts b/packages/eslint-plugin-internal/tests/rules/prefer-ast-types-enum.test.ts
@@ -0,0 +1,50 @@
+import rule from '../../src/rules/prefer-ast-types-enum';
+import { RuleTester, batchedSingleLineTests } from '../RuleTester';
+
+const ruleTester = new RuleTester({
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    sourceType: 'module',
+  },
+});
+
+ruleTester.run('prefer-ast-types-enum', rule, {
+  valid: [
+    'node.type === "constructor"',
+    'node.type === AST_NODE_TYPES.Literal',
+    'node.type === AST_TOKEN_TYPES.Keyword',
+    'node.type === 1',
+    `
+    enum MY_ENUM {
+      Literal = 1
+    }
+    `,
+    `
+    enum AST_NODE_TYPES {
+      Literal = 'Literal'
+    }
+    `,
+  ],
+  invalid: batchedSingleLineTests({
+    code: `
+node.type === 'Literal'
+node.type === 'Keyword'
+    `,
+    output: `
+node.type === AST_NODE_TYPES.Literal
+node.type === AST_TOKEN_TYPES.Keyword
+    `,
+    errors: [
+      {
+        data: { enumName: 'AST_NODE_TYPES', literal: 'Literal' },
+        messageId: 'preferEnum',
+        line: 2,
+      },
+      {
+        data: { enumName: 'AST_TOKEN_TYPES', literal: 'Keyword' },
+        messageId: 'preferEnum',
+        line: 3,
+      },
+    ],
+  }),
+});