feat(eslint-plugin): [no-explicit-any] ignoreRestArgs (#548)

typescript-eslint · Jun 16, 2019 · 753ad75 · 753ad75
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diff --git a/packages/eslint-plugin/docs/rules/no-explicit-any.md b/packages/eslint-plugin/docs/rules/no-explicit-any.md
@@ -87,6 +87,52 @@ function greet(param: Array<string>): string {}
 function greet(param: Array<string>): Array<string> {}
 ```
 
+### ignoreRestArgs
+
+A boolean to specify if arrays from the rest operator are considered okay. `false` by default.
+
+Examples of **incorrect** code for the `{ "ignoreRestArgs": false }` option:
+
+```ts
+/*eslint @typescript-eslint/no-explicit-any: ["error", { "ignoreRestArgs": false }]*/
+
+function foo1(...args: any[]): void {}
+function foo2(...args: readonly any[]): void {}
+function foo3(...args: Array<any>): void {}
+function foo4(...args: ReadonlyArray<any>): void {}
+
+const bar1 = (...args: any[]): void {}
+const bar2 = (...args: readonly any[]): void {}
+const bar3 = (...args: Array<any>): void {}
+const bar4 = (...args: ReadonlyArray<any>): void {}
+
+const baz1 = function (...args: any[]) {}
+const baz2 = function (...args: readonly any[]) {}
+const baz3 = function (...args: Array<any>) {}
+const baz4 = function (...args: ReadonlyArray<any>) {}
+```
+
+Examples of **correct** code for the `{ "ignoreRestArgs": true }` option:
+
+```ts
+/*eslint @typescript-eslint/no-explicit-any: ["error", { "ignoreRestArgs": true }]*/
+
+function foo1(...args: any[]): void {}
+function foo2(...args: readonly any[]): void {}
+function foo3(...args: Array<any>): void {}
+function foo4(...args: ReadonlyArray<any>): void {}
+
+const bar1 = (...args: any[]): void {}
+const bar2 = (...args: readonly any[]): void {}
+const bar3 = (...args: Array<any>): void {}
+const bar4 = (...args: ReadonlyArray<any>): void {}
+
+const baz1 = function (...args: any[]) {}
+const baz2 = function (...args: readonly any[]) {}
+const baz3 = function (...args: Array<any>) {}
+const baz4 = function (...args: ReadonlyArray<any>) {}
+```
+
 ## When Not To Use It
 
 If an unknown type or a library without typings is used

diff --git a/packages/eslint-plugin/src/rules/no-explicit-any.ts b/packages/eslint-plugin/src/rules/no-explicit-any.ts
@@ -1,3 +1,7 @@
+import {
+  TSESTree,
+  AST_NODE_TYPES,
+} from '@typescript-eslint/experimental-utils';
 import * as util from '../util';
 
 export default util.createRule({
@@ -12,12 +16,145 @@ export default util.createRule({
     messages: {
       unexpectedAny: 'Unexpected any. Specify a different type.',
     },
-    schema: [],
+    schema: [
+      {
+        type: 'object',
+        additionalProperties: false,
+        properties: {
+          ignoreRestArgs: {
+            type: 'boolean',
+          },
+        },
+      },
+    ],
   },
-  defaultOptions: [],
-  create(context) {
+  defaultOptions: [
+    {
+      ignoreRestArgs: false,
+    },
+  ],
+  create(context, [{ ignoreRestArgs }]) {
+    /**
+     * Checks if the node is an arrow function, function declaration or function expression
+     * @param node the node to be validated.
+     * @returns true if the node is an arrow function, function declaration or function expression
+     * @private
+     */
+    function isNodeValidFunction(node: TSESTree.Node): boolean {
+      return [
+        AST_NODE_TYPES.ArrowFunctionExpression,
+        AST_NODE_TYPES.FunctionDeclaration,
+        AST_NODE_TYPES.FunctionExpression,
+      ].includes(node.type);
+    }
+
+    /**
+     * Checks if the node is a rest element child node of a function
+     * @param node the node to be validated.
+     * @returns true if the node is a rest element child node of a function
+     * @private
+     */
+    function isNodeRestElementInFunction(node: TSESTree.Node): boolean {
+      return (
+        node.type === AST_NODE_TYPES.RestElement &&
+        typeof node.parent !== 'undefined' &&
+        isNodeValidFunction(node.parent)
+      );
+    }
+
+    /**
+     * Checks if the node is a TSTypeOperator node with a readonly operator
+     * @param node the node to be validated.
+     * @returns true if the node is a TSTypeOperator node with a readonly operator
+     * @private
+     */
+    function isNodeReadonlyTSTypeOperator(node: TSESTree.Node): boolean {
+      return (
+        node.type === AST_NODE_TYPES.TSTypeOperator &&
+        node.operator === 'readonly'
+      );
+    }
+
+    /**
+     * Checks if the node is a TSTypeReference node with an Array identifier
+     * @param node the node to be validated.
+     * @returns true if the node is a TSTypeReference node with an Array identifier
+     * @private
+     */
+    function isNodeValidArrayTSTypeReference(node: TSESTree.Node): boolean {
+      return (
+        node.type === AST_NODE_TYPES.TSTypeReference &&
+        typeof node.typeName !== 'undefined' &&
+        node.typeName.type === AST_NODE_TYPES.Identifier &&
+        ['Array', 'ReadonlyArray'].includes(node.typeName.name)
+      );
+    }
+
+    /**
+     * Checks if the node is a valid TSTypeOperator or TSTypeReference node
+     * @param node the node to be validated.
+     * @returns true if the node is a valid TSTypeOperator or TSTypeReference node
+     * @private
+     */
+    function isNodeValidTSType(node: TSESTree.Node): boolean {
+      return (
+        isNodeReadonlyTSTypeOperator(node) ||
+        isNodeValidArrayTSTypeReference(node)
+      );
+    }
+
+    /**
+     * Checks if the great grand-parent node is a RestElement node in a function
+     * @param node the node to be validated.
+     * @returns true if the great grand-parent node is a RestElement node in a function
+     * @private
+     */
+    function isGreatGrandparentRestElement(node: TSESTree.Node): boolean {
+      return (
+        typeof node.parent !== 'undefined' &&
+        typeof node.parent.parent !== 'undefined' &&
+        typeof node.parent.parent.parent !== 'undefined' &&
+        isNodeRestElementInFunction(node.parent.parent.parent)
+      );
+    }
+
+    /**
+     * Checks if the great great grand-parent node is a valid RestElement node in a function
+     * @param node the node to be validated.
+     * @returns true if the great great grand-parent node is a valid RestElement node in a function
+     * @private
+     */
+    function isGreatGreatGrandparentRestElement(node: TSESTree.Node): boolean {
+      return (
+        typeof node.parent !== 'undefined' &&
+        typeof node.parent.parent !== 'undefined' &&
+        isNodeValidTSType(node.parent.parent) &&
+        typeof node.parent.parent.parent !== 'undefined' &&
+        typeof node.parent.parent.parent.parent !== 'undefined' &&
+        isNodeRestElementInFunction(node.parent.parent.parent.parent)
+      );
+    }
+
+    /**
+     * Checks if the great grand-parent or the great great grand-parent node is a RestElement node
+     * @param node the node to be validated.
+     * @returns true if the great grand-parent or the great great grand-parent node is a RestElement node
+     * @private
+     */
+    function isNodeDescendantOfRestElementInFunction(
+      node: TSESTree.Node,
+    ): boolean {
+      return (
+        isGreatGrandparentRestElement(node) ||
+        isGreatGreatGrandparentRestElement(node)
+      );
+    }
+
     return {
       TSAnyKeyword(node) {
+        if (ignoreRestArgs && isNodeDescendantOfRestElementInFunction(node)) {
+          return;
+        }
         context.report({
           node,
           messageId: 'unexpectedAny',

diff --git a/packages/eslint-plugin/tests/rules/no-explicit-any.test.ts b/packages/eslint-plugin/tests/rules/no-explicit-any.test.ts
@@ -129,6 +129,63 @@ type obj = {
     message: string & Array<Array<string>>;
 }
         `,
+    // https://github.com/eslint/typescript-eslint-parser/issues/397
+    {
+      code: `
+        function foo(a: number, ...rest: any[]): void {
+          return;
+        }
+      `,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `function foo1(...args: any[]) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const bar1 = function (...args: any[]) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const baz1 = (...args: any[]) => {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `function foo2(...args: readonly any[]) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const bar2 = function (...args: readonly any[]) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const baz2 = (...args: readonly any[]) => {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `function foo3(...args: Array<any>) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const bar3 = function (...args: Array<any>) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const baz3 = (...args: Array<any>) => {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `function foo4(...args: ReadonlyArray<any>) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const bar4 = function (...args: ReadonlyArray<any>) {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
+    {
+      code: `const baz4 = (...args: ReadonlyArray<any>) => {}`,
+      options: [{ ignoreRestArgs: true }],
+    },
   ],
   invalid: [
     {
@@ -679,5 +736,53 @@ type obj = {
         },
       ],
     },
+    {
+      // https://github.com/eslint/typescript-eslint-parser/issues/397
+      code: `
+        function foo(a: number, ...rest: any[]): void {
+          return;
+        }
+      `,
+      errors: [
+        {
+          messageId: 'unexpectedAny',
+          line: 2,
+          column: 42,
+        },
+      ],
+    },
+    {
+      code: `function foo5(...args: any) {}`,
+      options: [{ ignoreRestArgs: true }],
+      errors: [
+        {
+          messageId: 'unexpectedAny',
+          line: 1,
+          column: 24,
+        },
+      ],
+    },
+    {
+      code: `const bar5 = function (...args: any) {}`,
+      options: [{ ignoreRestArgs: true }],
+      errors: [
+        {
+          messageId: 'unexpectedAny',
+          line: 1,
+          column: 33,
+        },
+      ],
+    },
+    {
+      code: `const baz5 = (...args: any) => {}`,
+      options: [{ ignoreRestArgs: true }],
+      errors: [
+        {
+          messageId: 'unexpectedAny',
+          line: 1,
+          column: 24,
+        },
+      ],
+    },
   ],
 });