ESLint VS lint-staged

ESLint: A pluggable and configurable linter tool for identifying and reporting on patterns in JavaScript.

Automating code checks with static code analysis allows us to enforce code styling effectively. By integrating tools into our workflow, we can identify errors at an early stage, while coding instead of blocking us at the end. For instance, flake8 checks Python code for style and errors, eslint performs similar checks for JavaScript, and prettier automatically formats code to maintain consistency.

If you're a developer, you're surely familiar with Prettier and ESLint. With over 8 years of existence, they have established themselves as references in the JavaScript ecosystem.

eslint is used to avoid code errors

No lint errors: The committed code does not contain any lint errors (eslint).

Let’s walk through the steps for a one-time setup to configure husky pre-commit and pre-push hooks, ESLint with code styles conventions, prettier code formatter, and lint-staged. Husky automatically runs a script on each commit or push. This is useful for linting files to enforce code styles that keeps the entire code base following conventions.

GitHub | Website

ESLint: A pluggable and configurable linter tool for identifying and reporting on patterns in JavaScript.

ESLint

1. Lack of Static Code Analysis Static code analysis tools like TypeScript and ESLint play a crucial role in identifying and preventing bugs. TypeScript provides static typing, enhancing the robustness of the code. ESLint detects issues and enforces coding standards. The absence of these tools can significantly elevate the likelihood of bugs due to the lack of early detection and guidance provided during development.

We were already using lint-staged and have a pre-commit hook in place using Husky in our project for linter and prettier. So it made sense to add a check here.

Now you can config it in your package.json, here is the guide doc:

In the world of software development, maintaining consistent code quality and ensuring that the codebase adheres to predefined patterns and guidelines is crucial. However, manually enforcing these standards can be time-consuming and error-prone. This is where automation tools like Husky, Lint-Staged, Commitlint, and Commitizen come to the rescue. In this post, we will explore how these tools can be combined to streamline your development workflow.

This is wasted work that can and should be automated. Adding a linter and formatter on CI and a pre-commit hook such as lint-staged can do wonders.

lint-staged is a package that can be used to run formatting and linting commands on staged files in a Git repo.

To answer your next question: I lint and format on save, and I use Git hooks installed by Husky and executed through Lint-Staged (this tool helps ensure your Git hooks only run on modified files, etc) to ensure there are no lint or formatting errors whenever making a commit or pushing code. This is helpful for teams, as some developers tend to forget to run lint tasks, or don't have the Prettier extension installed in their IDE. If there are lint errors, the commit is rejected until fixed. YMMV - you'll need to fine-tune the strictness of this based on the team's needs.

Uses Husky Git hooks and Lint-staged pre-commit hooks.

Something else to consider is applying linting and formatting before every git commit. A package like Lint-staged only lints and formats on staged items, ensuring all pushed code follows the standards in the repo. This allows developers to have their own formatting preferences when developing, while the code homogenizes on push. Linting pre-commit also avoids strict rules like no-console or no-unused-vars restricting a developer when writing code, when it should only apply in production. Imagine not being able to console log anything during development!

Lint-Staged Docs

Additionally, there are pre-commit hooks which can be setup to seamlessly validate and modify the source code before every commit. I followed Prettier documentation to create one. I ran npx mrm@2 lint-staged which installed husky and lint-stagedand added a configuration to the project’s package.json. Then, I modified the commands a little and that's it.