Warn on unused ESLint disable directives in base config (#829)

Author: bmish

README.md

@@ -18,16 +18,15 @@ Install alongside ESLint via yarn (or npm):
 yarn add --dev eslint eslint-plugin-square npm-run-all
 ```
 
-Edit your `.eslintrc.js` configuration file to extend one of the available configurations from this plugin and [detect unused disable directives](https://eslint.org/docs/latest/user-guide/configuring/rules#report-unused-eslint-disable-comments):
+Edit your `.eslintrc.js` configuration file to extend one of the available configurations from this plugin:
 
 ```js
 module.exports = {
-  reportUnusedDisableDirectives: true,
   extends: ['plugin:square/base'], // Or other configuration.
 };
 ```
 
-Add the relevant lint scripts in `package.json` with [npm-run-all](https://github.com/mysticatea/npm-run-all):
+Add the relevant lint scripts in `package.json` with [npm-run-all](https://github.com/mysticatea/npm-run-all) and include detection for [unused disable directives](https://eslint.org/docs/latest/user-guide/command-line-interface#--report-unused-disable-directives):
 
 ```json
 {

lib/config/base.js

@@ -3,6 +3,7 @@
 // This configuration is intended for use with JavaScript applications.
 
 module.exports = {
+  reportUnusedDisableDirectives: true, // Warn on unused disable directives: https://eslint.org/docs/latest/user-guide/configuring/rules#report-unused-eslint-disable-comments
   extends: [
     'eslint:recommended',
     'plugin:eslint-comments/recommended',

package.json

@@ -28,7 +28,7 @@
     "lint": "npm-run-all --continue-on-error --aggregate-output --parallel lint:*",
     "lint:docs": "markdownlint \"**/*.md\"",
     "lint:eslint-docs": "npm-run-all \"update:eslint-docs -- --check\"",
-    "lint:js": "eslint --cache .",
+    "lint:js": "eslint --report-unused-disable-directives --cache .",
     "lint:package-json": "npmPkgJsonLint .",
     "lint:package-json-sorting": "sort-package-json --check",
     "lint:package-json-sorting:fix": "sort-package-json package.json",