fix: webpack ESLintPlugin honours SKIP_PREFLIGHT_CHECK (facebook#9887)

Author: abraidwood

packages/react-scripts/config/webpack.config.js

@@ -62,6 +62,9 @@ const imageInlineSizeLimit = parseInt(
 // Check if TypeScript is setup
 const useTypeScript = fs.existsSync(paths.appTsConfig);
 
+// Check SKIP_PREFLIGHT_CHECK to disable ESLint
+const useESLint = process.env.SKIP_PREFLIGHT_CHECK === 'true';
+
 // Get the path to the uncompiled service worker (if it exists).
 const swSrc = paths.swSrc;
 
@@ -746,7 +749,7 @@ module.exports = function (webpackEnv) {
           // The formatter is invoked directly in WebpackDevServerUtils during development
           formatter: isEnvProduction ? typescriptFormatter : undefined,
         }),
-      new ESLintPlugin({
+      useESLint && new ESLintPlugin({
         // Plugin options
         extensions: ['js', 'mjs', 'jsx', 'ts', 'tsx'],
         formatter: require.resolve('react-dev-utils/eslintFormatter'),