From ae67c5ac45a8044fc1db66aee8eae6e881d660e4 Mon Sep 17 00:00:00 2001
From: Tom Spencer <tom.spencer@studiozeffa.com>
Date: Thu, 2 Dec 2021 14:42:03 -0800
Subject: [PATCH] Disable ESLint `no-undef` for TypeScript files (#32655)

Summary:
The `typescript-eslint` project [recommends that `no-undef` is disabled for TypeScript files](https://github.com/typescript-eslint/typescript-eslint/blob/6c3816b3831e6e683c1a7842196b34248803d69b/docs/linting/TROUBLESHOOTING.md#i-get-errors-from-the-no-undef-rule-about-global-variables-not-being-defined-even-though-there-are-no-typescript-errors), since TypeScript itself will perform this check. Disabling this config property has two benefits:

- Undefined variables and types will only be reported once, by the TypeScript compiler. Currently they are reported twice: once by TypeScript, and once by ESLint:

<img width="506" alt="Screenshot 2021-11-24 at 12 38 22" src="https://user-images.githubusercontent.com/820863/143239961-eb8ed709-60f9-490a-bda3-fc581673d56c.png">

- Types that are declared globally by React Native will no longer be erroneously reported as undefined - this is currently the case for some types, e.g. `Blob`:

<img width="419" alt="Screenshot 2021-11-24 at 12 40 04" src="https://user-images.githubusercontent.com/820863/143240213-06428b24-09c8-4f95-8e77-7f4fd160eed1.png">

## Changelog

<!-- Help reviewers and the release process by writing your own changelog entry. For an example, see:
https://github.com/facebook/react-native/wiki/Changelog
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[General] [Fixed] - ESLint no-undef rule clashing with TypeScript compiler for TS files

Pull Request resolved: https://github.com/facebook/react-native/pull/32655

Test Plan:
- Before: ESLint reporting on undefined variables in TypeScript files
- After: ESLint no longer reporting on undefined variables in TypeScript files

Reviewed By: GijsWeterings

Differential Revision: D32647147

Pulled By: yungsters

fbshipit-source-id: 070c734ac7a075b556492726c8fecf4fdab65898
---
 packages/eslint-config-react-native-community/index.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/eslint-config-react-native-community/index.js b/packages/eslint-config-react-native-community/index.js
index b9b7ee2273491d..e57ae48b77c660 100644
--- a/packages/eslint-config-react-native-community/index.js
+++ b/packages/eslint-config-react-native-community/index.js
@@ -58,6 +58,7 @@ module.exports = {
         'no-unused-vars': 'off',
         'no-shadow': 'off',
         '@typescript-eslint/no-shadow': 1,
+        'no-undef': 'off',
       },
     },
     {