---
id: javascript
sidebar_label: JavaScript
title: JavaScript FAQs
---

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## One of my lint rules isn't working correctly on a pure JavaScript file

This is to be expected - ESLint rules do not check file extensions on purpose, as it causes issues in environments that use non-standard extensions (for example, a `.vue` and a `.md` file can both contain TypeScript code to be linted).

If you have some pure JavaScript code that you do not want to apply certain lint rules to, then you can use [ESLint's `files` configuration](https://eslint.org/docs/latest/use/configure/configuration-files#specifying-files-and-ignores) to either:

- (recommended) only enable TypeScript-specific rules on TypeScript file extensions
- turn off TypeScript-specific rules on JavaScript-only file extensions

## Should I run ESLint on transpiled output JavaScript files?

No.

Source TypeScript files have all the content of output JavaScript files, plus type annotations.
There's no benefit to also linting output JavaScript files.
