Linting

Linting is the process of running a program that analyzes your code for potential errors, stylistic issues, and suspicious constructs. These programs, known as linters, can help identify issues in your codebase that might not be immediately apparent, ensuring that your code adheres to a set of predefined standards and best practices.

Linting offers several benefits that can significantly enhance the quality and maintainability of your code:

  1. Error Detection: Linters can catch syntactical errors, typos, and other mistakes that could cause runtime errors or bugs.
  2. Code Consistency: By enforcing coding standards and style guidelines, linting ensures that your code is uniform, making it easier to read and maintain.
  3. Early Issue Identification: Linting helps identify potential issues early in the development process, reducing the likelihood of bugs and improving code quality from the outset.

Qlty offers 40+ linters as plugins with a unified developer experience.

Linting is provided by Qlty CLI and Qlty Cloud.

How Linting Works

Linters analyze your code based on a set of rules or guidelines. These rules can be standard ones provided by the linter or custom rules defined by your development team. When the linter runs, it examines your code and flags any lines that violate these rules, often providing suggestions for how to fix the issues.

Here’s a simple example in JavaScript using ESLint, a popular linter:

1// Bad example
2var foo = "bar";
3if (foo == "bar") {
4    console.log("Hello, world!");
5}
6
7// Good example
8const foo = "bar";
9if (foo === "bar") {
10    console.log("Hello, world!");
11}

In this example, ESLint might flag the use of var instead of const, and the use of == instead of ===, promoting better coding practices.

Integrating Linting into Your Workflow

Unlike more advanced static analysis, linters typically run quickly and on a per-file basis. This makes them well suited to run frequently.

Qlty makes it easy to integrate linting directly into your development workflow:

  • Pre-commit Hooks: Running the Qlty CLI’s qlty check command before committing code to your version control system, preventing issues from being introduced.
  • Automated Code Review: Qlty Cloud can automatically run linters on your pull requests and post any identified issues as comments.

See Also