typescript-eslint · mahdi-farnia · Oct 18, 2022 · Oct 19, 2022 · Oct 19, 2022 · Oct 19, 2022
diff --git a/packages/eslint-plugin/docs/rules/call-super-on-override.md b/packages/eslint-plugin/docs/rules/call-super-on-override.md
@@ -0,0 +1,40 @@
+---
+description: 'Require overridden methods to call super.method in their body.'
+---
+
+> 🛑 This file is source code, not the primary documentation location! 🛑
+>
+> See **https://typescript-eslint.io/rules/call-super-on-override** for documentation.
+
+This rule enforces that overridden methods call their corresponding `super` method.
+Doing so can be useful in architectures where base class methods are meant to always be called by child classes.
+
+## Rule Details
+
+Examples of code for this rule:
+
+### ❌ Incorrect
+
+```ts
+class Foo1 {
+  bar(param: any): void {}
+}
+
+class Foo2 extends Foo1 {
+  override bar(param: any): void {}
+}
+```
+
+### ✅ Correct
+
+```ts
+class Foo1 {
+  bar(param: any): void {}
+}
+
+class Foo2 extends Foo1 {
+  override bar(param: any): void {
+    super.bar(param);
+  }
+}
+```
diff --git a/packages/eslint-plugin/src/configs/all.ts b/packages/eslint-plugin/src/configs/all.ts
@@ -15,6 +15,7 @@ export = {
     '@typescript-eslint/block-spacing': 'error',
     'brace-style': 'off',
     '@typescript-eslint/brace-style': 'error',
+    '@typescript-eslint/call-super-on-override': 'error',
     '@typescript-eslint/class-literal-property-style': 'error',
     'comma-dangle': 'off',
     '@typescript-eslint/comma-dangle': 'error',

diff --git a/packages/eslint-plugin/src/rules/call-super-on-override.ts b/packages/eslint-plugin/src/rules/call-super-on-override.ts
@@ -0,0 +1,106 @@
+import type { TSESTree } from '@typescript-eslint/utils';
+import { AST_NODE_TYPES } from '@typescript-eslint/utils';
+
+import * as utils from '../util';
+
+/**
+ * TODO:
+ * 1. Grabbing the type of the extended class
+ * 2. Checking whether it has a method / function property under the same name
+ */
+
+export default utils.createRule({
+  name: 'call-super-on-override',
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description:
+        'Require overridden methods to call super.method in their body',
+      recommended: false,
+    },
+    messages: {
+      missingSuperMethodCall:
+        "Use 'super{{property}}{{parameterTuple}}' to avoid missing super class method implementations",
+    },
+    fixable: 'code',
+    schema: [],
+  },
+  defaultOptions: [],
+  create(context) {
+    return {
+      'MethodDefinition[override=true][kind="method"]'(
+        node: TSESTree.MethodDefinition,
+      ): void {
+        const methodName =
+          node.key.type === AST_NODE_TYPES.Identifier
+            ? node.key.name
+            : (node.key as TSESTree.Literal).value?.toString() ?? 'null';
+        const methodNameIsLiteral = node.key.type === AST_NODE_TYPES.Identifier;
+        const methodNameIsNull =
+          node.key.type !== AST_NODE_TYPES.Identifier
+            ? (node.key as TSESTree.Literal).value == null
+            : false;
+
+        const { computed: isComputed } = node;
+        const bodyStatements = node.value.body!.body;
+
+        for (const statement of bodyStatements) {
+          if (
+            isSuperMethodCall(
+              statement,
+              methodName,
+              !methodNameIsLiteral && isComputed,
+            )
+          ) {
+            return;
+          }
+        }
+
+        context.report({
+          messageId: 'missingSuperMethodCall',
+          node: node,
+          data: {
+            property: isComputed
+              ? `[${
+                  methodNameIsLiteral && !methodNameIsNull
+                    ? `'${methodName}'`
+                    : methodName
+                }]`
+              : `.${methodName}`,
+            parameterTuple: `(${node.value.params
+              .map(p => (p as TSESTree.Identifier).name)
+              .join(', ')})`,
+          },
+        });
+      },
+    };
+  },
+});
+
+const isSuperMethodCall = (
+  statement: TSESTree.Statement | undefined,
+  methodName: string,
+  methodIsComputedIdentifier: boolean,
+): boolean => {
+  // for edge cases like this -> override [X]() { super.X() }
+  // we make sure that computed identifier should have computed callback
+  let calleeIsComputedIdentifier = false;
+
+  const calleeName =
+    statement?.type === AST_NODE_TYPES.ExpressionStatement &&
+    statement.expression.type === AST_NODE_TYPES.CallExpression &&
+    statement.expression.callee.type === AST_NODE_TYPES.MemberExpression &&
+    statement.expression.callee.object.type === AST_NODE_TYPES.Super &&
+    (statement.expression.callee.property.type === AST_NODE_TYPES.Identifier
+      ? ((calleeIsComputedIdentifier = statement.expression.callee.computed),
+        statement.expression.callee.property.name)
+      : statement.expression.callee.property.type === AST_NODE_TYPES.Literal
+      ? statement.expression.callee.property.value?.toString() ?? 'null'
+      : undefined);
+
+  return methodIsComputedIdentifier
+    ? calleeIsComputedIdentifier
+      ? methodName === calleeName
+      : false
+    : methodName === calleeName;
+};
diff --git a/packages/eslint-plugin/src/rules/index.ts b/packages/eslint-plugin/src/rules/index.ts
@@ -6,6 +6,7 @@ import banTslintComment from './ban-tslint-comment';
 import banTypes from './ban-types';
 import blockSpacing from './block-spacing';
 import braceStyle from './brace-style';
+import callSuperOnOverride from './call-super-on-override';
 import classLiteralPropertyStyle from './class-literal-property-style';
 import commaDangle from './comma-dangle';
 import commaSpacing from './comma-spacing';
@@ -142,6 +143,7 @@ export default {
   'ban-types': banTypes,
   'block-spacing': blockSpacing,
   'brace-style': braceStyle,
+  'call-super-on-override': callSuperOnOverride,
   'class-literal-property-style': classLiteralPropertyStyle,
   'comma-dangle': commaDangle,
   'comma-spacing': commaSpacing,

diff --git a/packages/eslint-plugin/tests/rules/call-super-on-override.test.ts b/packages/eslint-plugin/tests/rules/call-super-on-override.test.ts
@@ -0,0 +1,121 @@
+import rule from '../../src/rules/call-super-on-override';
+import { RuleTester } from '../RuleTester';
+
+const ruleTester = new RuleTester({
+  parser: '@typescript-eslint/parser',
+});
+
+ruleTester.run('call-super-on-override', rule, {
+  valid: [
+    {
+      code: `
+class ValidSample {
+  override x() {
+    this.y();
+    super.x();
+  }
+}
+      `,
+    },
+    {
+      code: `
+class ValidSample {
+  override ['x-y']() {
+    super['x-y']();
+  }
+  override ['z']() {
+    super.z();
+  }
+  override h() {
+    super['h']();
+  }
+  override [M]() {
+    super[M]();
+  }
+}
+      `,
+    },
+  ],
+  invalid: [
+    {
+      code: `
+class InvalidSample {
+  override x() {
+    this.x();
+    super.x = () => void 0;
+    super.x;
+  }
+}
+      `,
+      errors: [
+        {
+          messageId: 'missingSuperMethodCall',
+          data: { property: '.x', parameterTuple: '()' },
+        },
+      ],
+    },
+    {
+      code: `
+class InvalidSample {
+  override ['x-y-z']() {
+    this['x-y-z']();
+    super['x-y-z'] = () => void 0;
+    super['x-y-z'];
+  }
+}
+      `,
+      errors: [
+        {
+          messageId: 'missingSuperMethodCall',
+          data: { property: "['x-y-z']", parameterTuple: '()' },
+        },
+      ],
+    },
+    {
+      code: `
+class InvalidSample {
+  override x(y: number, z: string) {}
+}
+      `,
+      errors: [
+        {
+          messageId: 'missingSuperMethodCall',
+          data: { property: '.x', parameterTuple: '(y, z)' },
+        },
+      ],
+    },
+    {
+      code: `
+class InvalidSample {
+  override [M]() {
+    super.M();
+  }
+}
+      `,
+      errors: [
+        {
+          messageId: 'missingSuperMethodCall',
+          data: { property: '[M]', parameterTuple: '()' },
+        },
+      ],
+    },
+    {
+      code: `
+class InvalidSample {
+  override [null]() {}
+  override ['null']() {}
+}
+      `,
+      errors: [
+        {
+          messageId: 'missingSuperMethodCall',
+          data: { property: '[null]', parameterTuple: '()' },
+        },
+        {
+          messageId: 'missingSuperMethodCall',
+          data: { property: "['null']", parameterTuple: '()' },
+        },
+      ],
+    },
+  ],
+});