feat: add enableJavaScriptSpecificRulesInTypeScriptProject createCo…

…nfig argument

- `enableJavaScriptSpecificRulesInTypeScriptProject` skips disabling JS specific rules that are shadowed by typescript in situations where you still want to fully lint JS files but cannot use checkJs in tsconfig

README.md

@@ -140,6 +140,28 @@ This way, you can customize it entirely to your likings without having to create
 
 </details>
 
+<details>
+  <summary>Migrating a codebase to TypeScript</summary>
+
+While in the process of migration, you may end up in a situation where you cannot turn on `compilerOptions.checkJs` from TypeScript itself due to e.g. builds breaking. However, by default certain rules will be disabled for JavaScript files because they are technically shadowed by TypeScript itself, e.g. `no-undef`.
+
+You can opt out of this behaviour by either:
+
+- passing `enableJavaScriptSpecificRulesInTypeScriptProject` as `true` to `createConfig`
+- enabling `compilerOptions.checkJs` once you're there
+
+Example:
+
+```js
+const { createConfig } = require('eslint-config-galex/dist/createConfig');
+
+module.exports = createConfig({
+  enableJavaScriptSpecificRulesInTypeScriptProject: true,
+});
+```
+
+</details>
+
 # Examples
 
 <details>

__tests__/integration.test.ts

@@ -77,6 +77,10 @@ const cases = [
     name: 'js ts migration mix checkJs on',
     path: 'js-ts-migration-mix-checkJs-on',
   },
+  {
+    name: 'js ts migration force js linting in ts',
+    path: 'js-ts-migration-mix-force-js-linting',
+  },
 ];
 
 describe.each(cases)('$case.name', ({ path, name }) => {

integration/abstractConfig.js

@@ -19,9 +19,20 @@ if (!process.argv.some(arg => arg.includes('vscode-eslint'))) {
     parser: 'json-stringify',
   };
 
+  let extraArgs = {};
+
+  if (process.env.createConfigArgs) {
+    extraArgs = JSON.parse(process.env.createConfigArgs);
+
+    console.log(
+      `running createConfig with extra arguments: ${process.env.createConfigArgs}`
+    );
+  }
+
   const config = createConfig({
     root: true,
     cwd,
+    ...extraArgs,
   });
 
   const depsPath = resolve('deps.json');

integration/js-ts-migration-mix-force-js-linting/.eslintrc.js

@@ -0,0 +1,4 @@
+process.env.createConfigArgs = JSON.stringify({
+  enableJavaScriptSpecificRulesInTypeScriptProject: true,
+});
+module.exports = require('../abstractConfig');

integration/js-ts-migration-mix-force-js-linting/deps.json

@@ -0,0 +1,49 @@
+{
+  "hasJest": false,
+  "hasJestDom": false,
+  "hasNodeTypes": false,
+  "hasTestingLibrary": false,
+  "hasNest": false,
+  "storybook": {
+    "hasStorybook": false,
+    "hasStorybookTestingLibrary": false
+  },
+  "react": {
+    "hasReact": false,
+    "isCreateReactApp": false,
+    "isNext": false,
+    "isRemix": false,
+    "isPreact": false,
+    "version": null
+  },
+  "typescript": {
+    "config": {
+      "compilerOptions": {
+        "target": "es5",
+        "lib": [
+          "dom",
+          "dom.iterable",
+          "esnext"
+        ],
+        "allowJs": true,
+        "skipLibCheck": true,
+        "strict": true,
+        "forceConsistentCasingInFileNames": true,
+        "noEmit": true,
+        "esModuleInterop": true,
+        "module": "esnext",
+        "moduleResolution": "node",
+        "resolveJsonModule": true,
+        "isolatedModules": true
+      },
+      "include": [
+        "src"
+      ],
+      "exclude": [
+        "node_modules"
+      ]
+    },
+    "hasTypeScript": true,
+    "version": "4.6.4"
+  }
+}