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

packages/eslint-plugin/docs/rules/no-explicit-any.md

@@ -87,6 +87,23 @@ function greet(param: Array<string>): string {}
 function greet(param: Array<string>): Array<string> {}
 ```
 
+### Options
+
+This rule accepts a single object option with the following default configuration:
+
+```json
+{
+  "@typescript-eslint/no-explicit-any": [
+    "error",
+    {
+      "ignoreRestArgs": false
+    }
+  ]
+}
+```
+
+- `ignoreRestArgs: true` will disallow usages of `any` as a type declaration except rest spread parameters.
+
 ## When Not To Use It
 
 If an unknown type or a library without typings is used

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 +16,63 @@ 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 parent is a function declaration
+     * @param node the node to be validated.
+     * @returns true if the node parent is a function declaration
+     * @private
+     */
+    function isParentFunctionDeclaration(node: TSESTree.Node): boolean {
+      return (
+        typeof node.parent !== 'undefined' &&
+        node.parent.type === AST_NODE_TYPES.FunctionDeclaration
+      );
+    }
+
+    /**
+     * Checks if the node great granparent is a rest element
+     * @param node the node to be validated.
+     * @returns true if the node great granparent is a rest element
+     * @private
+     */
+    function isGreatGrandparentRestElementInFunctionDeclaration(
+      node: TSESTree.Node,
+    ): boolean {
+      return (
+        typeof node.parent !== 'undefined' &&
+        typeof node.parent.parent !== 'undefined' &&
+        typeof node.parent.parent.parent !== 'undefined' &&
+        node.parent.parent.parent.type === AST_NODE_TYPES.RestElement &&
+        isParentFunctionDeclaration(node.parent.parent.parent)
+      );
+    }
+
     return {
       TSAnyKeyword(node) {
+        if (
+          ignoreRestArgs &&
+          isGreatGrandparentRestElementInFunctionDeclaration(node)
+        ) {
+          return;
+        }
         context.report({
           node,
           messageId: 'unexpectedAny',

packages/eslint-plugin/tests/rules/no-explicit-any.test.ts

@@ -129,6 +129,15 @@ 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 }],
+    },
   ],
   invalid: [
     {
@@ -679,5 +688,20 @@ 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,
+        },
+      ],
+    },
   ],
 });