Prior to ESLint v9.0.0, the --output-file flag would skip writing a file to disk if the output was empty. However, in ESLint v9.0.0, --output-file now consistently writes a file to disk, even when the output is empty.

You have no counterpart to "extends", and 'eslint': "warn" results in an error because there's no such rule. Rules are these eslint.org/docs/latest/rules . I'd suggest to just create a new vue project and borrow the config from there ... Here what I'm trying to do is converting the eslint to v9.

November 7, 2024 - ESLint version HEAD What problem do you want to solve? Now that more folks are moving to ESLint v9 and flat config, a common complaint is that it's difficult to extend configs from plugins. Whereas eslintrc had extends, flat config force...

This page explains the ways to extend ESLint, and how these extensions all fit together.

July 12, 2024 - Refer to the official documentation: ... } } // ...other config } ]; In version 9.x.x, you can no longer use extends to include configurations like eslint:recommended....

When ESLint v9.0.0 was released in April 2024, we enabled the new configuration system by default. We knew that there would be a period of challenges as the ecosystem switched over.

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ESLint v9.x support was added in the vscode-eslint v3.0.10.

In v9.0.0, we updated the behavior of eslint-scope to fix a couple of longstanding bugs: Previously, ESLint would treat ("use strict") as a strict mode directive even though it is not.

March 19, 2025 - You can now use `defineConfig` from “eslint/config” to extend your configuration. This brings back the “extends” functionality, adds support for global ignores, and maintains compatibility with older plugins…etc.

Bug Fixes 650753e fix: Only pass node to JS lang visitor methods (#20283) (Nicholas C. Zakas) Documentation 51b51f4 docs: add a section on when to use extends vs cascading (#20268) (Tanuj Kanti)...

August 5, 2024 - That is because, before ESLint 9, it had many conflicts between IDE/Editor, prettier, and ESLint. Now ESLint9 disabled & deprecated some confict rules, and enabled Flat config as default.

thank you for making eslint more complicated, unusable, it motivates us to move to Biomes after spending 8 hours dealing with errors everywhere in the new config file, these sad after having used eslint for 7 years! the v9 was hellish for us, biomes work the first time in ....

So I just updated my eslint to v9 and with it the default configuration file was changed to eslint.config.js As someone who hasn't known about the configuration change at all, it was quite pain...

February 6, 2025 - The ESLint v9.0.0 was released in April 2024, and support for the v8.x version ends on the 5th of October 2024. Half a year for migration sounds like enough time, but the ninth version completely breaks backward compatibility with a new «flat ...

The main reason is that it's not generally possible in ESLint v9, like it was possible in ESLint v8, to write a config file in JSON format. For example, there is no longer a standard to resolve a shared config by name by specifying "my-config-module" in the extends field.

We just pushed ESLint v9.22.0, which is a minor release upgrade of ESLint. This release adds some new features and fixes several bugs found in the previous release. This release introduces the defineConfig() and globalIgnores() helpers for configuration files. The defineConfig() helper brings type safety into your configuration file and also enables you to use the new extends key.

March 18, 2025 - As a frontend developer who has spent years working with complex TypeScript codebases, I’ve learned that solid linting is essential for maintaining long-term code quality. With the release of ESLint v9 and its new flat configuration system, I knew it was time to upgrade — and face the inevitable challenges that come with major version changes.

import eslint from '@eslint/js'; import eslintConfigPrettier from 'eslint-config-prettier'; import eslintPluginVue from 'eslint-plugin-vue'; import globals from 'globals'; import typescriptEslint from 'typescript-eslint'; export default typescriptEslint.config( { ignores: ['*.d.ts', '**/coverage', '**/dist'] }, { extends: [ eslint.configs.recommended, ...typescriptEslint.configs.recommended, ...eslintPluginVue.configs['flat/recommended'], ], files: ['**/*.{ts,vue}'], languageOptions: { ecmaVersion: 'latest', sourceType: 'module', globals: globals.browser, parserOptions: { parser: typescriptEslint.parser, }, }, rules: { // your rules }, }, eslintConfigPrettier ); Use .eslintrc.* file to configure rules in ESLint < v9.