typescript-eslint · bradzacher · Feb 2, 2022 · Jan 14, 2022 · Jan 14, 2022 · Jan 24, 2022
diff --git a/packages/eslint-plugin/docs/rules/explicit-function-return-type.md b/packages/eslint-plugin/docs/rules/explicit-function-return-type.md
@@ -77,6 +77,10 @@ type Options = {
   allowDirectConstAssertionInArrowFunctions?: boolean;
   // if true, concise arrow functions that start with the void keyword will not be checked
   allowConciseArrowFunctionExpressionsStartingWithVoid?: boolean;
+  /**
+   * An array of function/method names that will not have their arguments or their return values checked.
+   */
+  allowedNames?: string[];
 };
 
 const defaults = {
@@ -85,6 +89,7 @@ const defaults = {
   allowHigherOrderFunctions: true,
   allowDirectConstAssertionInArrowFunctions: true,
   allowConciseArrowFunctionExpressionsStartingWithVoid: false,
+  allowedNames: [],
 };
 ```
 
@@ -262,6 +267,21 @@ const log = (message: string) => {
 var log = (message: string) => void console.log(message);
 ```
 
+### `allowedNames`
+
+You may pass function/method names you would like this rule to ignore, like so:
+
+```json
+{
+  "@typescript-eslint/explicit-function-return-type": [
+    "error",
+    {
+      "allowedNames": ["ignoredFunctionName", "ignoredMethodName"]
+    }
+  ]
+}
+```
+
 ## When Not To Use It
 
 If you don't wish to prevent calling code from using function return values in unexpected ways, then

diff --git a/packages/eslint-plugin/src/rules/explicit-function-return-type.ts b/packages/eslint-plugin/src/rules/explicit-function-return-type.ts
@@ -13,6 +13,7 @@ type Options = [
     allowHigherOrderFunctions?: boolean;
     allowDirectConstAssertionInArrowFunctions?: boolean;
     allowConciseArrowFunctionExpressionsStartingWithVoid?: boolean;
+    allowedNames?: string[];
   },
 ];
 type MessageIds = 'missingReturnType';
@@ -48,6 +49,12 @@ export default util.createRule<Options, MessageIds>({
           allowConciseArrowFunctionExpressionsStartingWithVoid: {
             type: 'boolean',
           },
+          allowedNames: {
+            type: 'array',
+            items: {
+              type: 'string',
+            },
+          },
         },
         additionalProperties: false,
       },
@@ -60,11 +67,64 @@ export default util.createRule<Options, MessageIds>({
       allowHigherOrderFunctions: true,
       allowDirectConstAssertionInArrowFunctions: true,
       allowConciseArrowFunctionExpressionsStartingWithVoid: false,
+      allowedNames: [],
     },
   ],
   create(context, [options]) {
     const sourceCode = context.getSourceCode();
+    function isAllowedName(
+      node:
+        | TSESTree.ArrowFunctionExpression
+        | TSESTree.FunctionExpression
+        | TSESTree.FunctionDeclaration,
+    ): boolean {
+      if (!options.allowedNames || !options.allowedNames.length) {
+        return false;
+      }
 
+      if (
+        node.type === AST_NODE_TYPES.ArrowFunctionExpression ||
+        node.type === AST_NODE_TYPES.FunctionExpression
+      ) {
+        const parent = node.parent;
+        let funcName;
+        if (node.id?.name) {
+          funcName = node.id.name;
+        } else if (parent) {
+          switch (parent.type) {
+            case AST_NODE_TYPES.VariableDeclarator: {
+              if (parent.id.type === AST_NODE_TYPES.Identifier) {
+                funcName = parent.id.name;
+              }
+              break;
+            }
+            case AST_NODE_TYPES.MethodDefinition:
+            case AST_NODE_TYPES.PropertyDefinition:
+            case AST_NODE_TYPES.Property: {
+              if (
+                parent.key.type === AST_NODE_TYPES.Identifier &&
+                parent.computed === false
+              ) {
+                funcName = parent.key.name;
+              }
+              break;
+            }
+          }
+        }
+        if (!!funcName && !!options.allowedNames.includes(funcName)) {
+          return true;
+        }
+      }
+      if (
+        node.type === AST_NODE_TYPES.FunctionDeclaration &&
+        node.id &&
+        node.id.type === AST_NODE_TYPES.Identifier &&
+        !!options.allowedNames.includes(node.id.name)
+      ) {
+        return true;
+      }
+      return false;
+    }
     return {
       'ArrowFunctionExpression, FunctionExpression'(
         node: TSESTree.ArrowFunctionExpression | TSESTree.FunctionExpression,
@@ -79,6 +139,10 @@ export default util.createRule<Options, MessageIds>({
           return;
         }
 
+        if (isAllowedName(node)) {
+          return;
+        }
+
         if (
           options.allowTypedFunctionExpressions &&
           (isValidFunctionExpressionReturnType(node, options) ||
@@ -96,6 +160,9 @@ export default util.createRule<Options, MessageIds>({
         );
       },
       FunctionDeclaration(node): void {
+        if (isAllowedName(node)) {
+          return;
+        }
         if (options.allowTypedFunctionExpressions && node.returnType) {
           return;
         }

diff --git a/packages/eslint-plugin/tests/rules/explicit-function-return-type.test.ts b/packages/eslint-plugin/tests/rules/explicit-function-return-type.test.ts
@@ -400,6 +400,99 @@ new Foo(1, () => {});
       code: 'const log = (message: string) => void console.log(message);',
       options: [{ allowConciseArrowFunctionExpressionsStartingWithVoid: true }],
     },
+    {
+      filename: 'test.ts',
+      options: [
+        {
+          allowedNames: ['test1', 'test2'],
+        },
+      ],
+      code: `
+function test1() {
+  return;
+}
+
+const foo = function test2() {
+  return;
+};
+      `,
+    },
+    {
+      filename: 'test.ts',
+      options: [
+        {
+          allowedNames: ['test1', 'test2'],
+        },
+      ],
+      code: `
+const test1 = function () {
+  return;
+};
+const foo = function () {
+  return function test2() {};
+};
+      `,
+    },
+    {
+      filename: 'test.ts',
+      options: [
+        {
+          allowedNames: ['test1', 'test2'],
+        },
+      ],
+      code: `
+const test1 = () => {
+  return;
+};
+export const foo = {
+  test2() {
+    return 0;
+  },
+};
+      `,
+    },
+    {
+      filename: 'test.ts',
+      code: `
+class Test {
+  constructor() {}
+  get prop() {
+    return 1;
+  }
+  set prop() {}
+  method() {
+    return;
+  }
+  arrow = () => 'arrow';
+  private method() {
+    return;
+  }
+}
+      `,
+      options: [
+        {
+          allowedNames: ['prop', 'method', 'arrow'],
+        },
+      ],
+    },
+    {
+      filename: 'test.ts',
+      code: `
+const x = {
+  arrowFn: () => {
+    return;
+  },
+  fn: function () {
+    return;
+  },
+};
+      `,
+      options: [
+        {
+          allowedNames: ['arrowFn', 'fn'],
+        },
+      ],
+    },
     {
       filename: 'test.ts',
       code: `
@@ -1226,5 +1319,100 @@ const func = (value: number) => ({ type: 'X', value } as const);
         },
       ],
     },
+    {
+      filename: 'test.ts',
+      options: [
+        {
+          allowedNames: ['test', '1'],
+        },
+      ],
+      code: `
+function hoge() {
+  return;
+}
+const foo = () => {
+  return;
+};
+const baz = function () {
+  return;
+};
+let [test, test] = function () {
+  return;
+};
+class X {
+  [test] = function () {
+    return;
+  };
+}
+const x = {
+  1: function () {
+    reutrn;
+  },
+};
+      `,
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 2,
+          endLine: 2,
+          column: 1,
+          endColumn: 16,
+        },
+        {
+          messageId: 'missingReturnType',
+          line: 5,
+          endLine: 5,
+          column: 13,
+          endColumn: 18,
+        },
+        {
+          messageId: 'missingReturnType',
+          line: 8,
+          endLine: 8,
+          column: 13,
+          endColumn: 24,
+        },
+        {
+          messageId: 'missingReturnType',
+          line: 11,
+          endLine: 11,
+          column: 20,
+          endColumn: 31,
+        },
+        {
+          line: 15,
+          column: 12,
+          messageId: 'missingReturnType',
+          endLine: 15,
+          endColumn: 23,
+        },
+        {
+          messageId: 'missingReturnType',
+          line: 20,
+          endLine: 20,
+          column: 6,
+          endColumn: 17,
+        },
+      ],
+    },
+    {
+      filename: 'test.ts',
+      code: `
+const ignoredName = 'notIgnoredName';
+class Foo {
+  [ignoredName]() {}
+}
+      `,
+      options: [{ allowedNames: ['ignoredName'] }],
+      errors: [
+        {
+          messageId: 'missingReturnType',
+          line: 4,
+          endLine: 4,
+          column: 3,
+          endColumn: 18,
+        },
+      ],
+    },
   ],
 });