JSLint vs. ESLint: Which JavaScript Linter Should You Choose?JavaScript linters analyze source code to catch mistakes, enforce style, and maintain consistency across a codebase. Two well-known tools in this space are JSLint and ESLint. Both aim to improve code quality, but they take different design approaches, offer different features, and suit different workflows. This article compares them across history, philosophy, configuration, rules, extensibility, ecosystem integration, performance, team workflows, and recommended use cases to help you choose the right tool for your project.
Background and philosophy
JSLint
- Created by Douglas Crockford in 2002 as one of the earliest JavaScript static analyzers.
- Opinionated by design: enforces a strict subset of JavaScript and a specific coding style.
- Goals: catch likely errors and promote a particular set of best practices; fewer configuration options to avoid “bike-shedding” over style.
ESLint
- Created by Nicholas C. Zakas in 2013 to address limitations of earlier linters like JSLint and JSHint.
- Designed for configurability and extensibility: you can enable/disable rules, create custom rules, and use plugins.
- Philosophy: provide a flexible platform that adapts to different projects and evolving JavaScript features.
Configuration and flexibility
JSLint
- Minimal configuration. The tool expects code to conform to its rules; options are limited.
- There’s a small set of directives to relax specific checks, but overall it resists heavy customization.
- This can be good for small teams that want a single, strict standard, but poor for diverse codebases or teams that need exceptions.
ESLint
- Highly configurable via .eslintrc.* files (JSON, YAML, or JS).
- Rule-level controls allow setting rules to “off”, “warn”, or “error”.
- Supports environments (browser, node, ES versions), parser options, globals, and overrides per-file or per-glob.
- Supports shareable configs (example: eslint-config-airbnb), enabling consistent rules across many projects.
Rules, error types, and maintainability
JSLint
- Focuses on preventing errors and enforcing a curated style.
- Rules are less numerous and often stricter; some valid code patterns are flagged intentionally.
- Rule changes come from project maintainers, not by plugin authors; updates can be opinion-driven.
ESLint
- Large rule set and a vibrant ecosystem of rule sets and plugins (React, TypeScript, security, accessibility, etc.).
- Rules cover stylistic concerns and potential errors; many teams split stylistic rules (handled by Prettier) and correctness rules (handled by ESLint).
- Easier to maintain in large or heterogenous codebases because you can evolve ruleset gradually and scope changes to file types or folders.
Extensibility: plugins, custom rules, and parsers
JSLint
- Limited extensibility. Creating custom rules or plugins is not a standard workflow.
- Not ideal for projects that need domain-specific checks or support for new syntactic constructs (e.g., JSX or TypeScript).
ESLint
- Built for extension. Plugins add rules and processors for frameworks and languages (React, Vue, TypeScript).
- Custom rules are straightforward to write and share.
- Supports alternative parsers (like @babel/eslint-parser or @typescript-eslint/parser) to handle modern or nonstandard syntax.
Language support and modern syntax
JSLint
- Historically aligned with core JavaScript and cautious about emerging language features.
- May lag in supporting new syntax or require workarounds.
ESLint
- Actively updated to support modern ECMAScript features via parser options and parsers.
- Community plugins quickly add support for JSX, TypeScript, and nonstandard transforms.
Tooling and editor integrations
JSLint
- Has integrations and online tools but fewer modern editor extensions compared to ESLint.
- Some editors offer built-in or community plugins, but real-time feedback and fixes are less extensive.
ESLint
- First-class integrations with VS Code, WebStorm, Sublime Text, and most editors.
- Supports auto-fix for many rules (eslint –fix), helpful in developer workflows and pre-commit hooks.
- Works well with formatters like Prettier (via disabling overlapping rules) to separate style from correctness.
CI/CD and automation
JSLint
- Can be run in CI, but less commonly integrated into modern pipelines and fewer community-maintained adapters.
ESLint
- Widely used in CI pipelines, can be run with –max-warnings, fail-on-error, or integrated into pre-commit hooks (husky, lint-staged).
- Ecosystem provides ready-made recipes for GitHub Actions, GitLab CI, and other systems.
Performance
- Both tools are fast for typical project sizes. ESLint’s plugin system can add overhead depending on rules and parsers used, but in practice performance is acceptable and optimizable (caching, running only staged files).
- JSLint’s smaller rule set often yields faster runs by default, but real-world differences are usually minor.
Community, maintenance, and ecosystem
JSLint
- Maintained but much smaller ecosystem and fewer community plugins or shared configs.
- Tends to be used by developers who prefer Crockford’s opinions or want a very strict, minimal-configuration linter.
ESLint
- Large community, active development, many plugins, and corporate adoption.
- Extensive documentation, numerous shared configs (Airbnb, Google, Standard), and third-party tooling.
Pros and cons
| Aspect | JSLint | ESLint |
|---|---|---|
| Philosophy | Opinionated, strict | Configurable, extensible |
| Configuration | Minimal | Highly configurable |
| Extensibility | Limited | Excellent (plugins, custom rules, parsers) |
| Modern syntax support | Slower to adopt | Quick via parsers/plugins |
| Editor & CI integrations | Limited | Extensive |
| Ecosystem | Small | Large |
| Suitability | Small teams wanting strict defaults | Most teams and larger projects |
Choosing which to use
-
Choose JSLint if:
- You want a tiny set of strong, opinionated rules and minimal configuration.
- You prefer Douglas Crockford’s style and constraints.
- Your project is small or you want to enforce a single strict standard without debate.
-
Choose ESLint if:
- You need flexibility, plugin support, or TypeScript/JSX integration.
- You want to gradually adopt linting rules or apply different rules per project area.
- You need strong editor and CI integration, auto-fix, and a large community.
Migration and coexistence
-
Migrating from JSLint to ESLint:
- Map JSLint rules to equivalent ESLint rules where possible, then enable or configure them.
- Introduce ESLint in stages—start with error-level rules (potential bugs), then add style rules.
- Use automatic fixes (eslint –fix) and lint-staged for incremental adoption.
-
Coexistence:
- Running both is uncommon and usually unnecessary. Pick ESLint if you need flexibility; JSLint’s strictness can be recreated via a strict ESLint config if desired.
Practical recommendation
For most modern projects, ESLint is the recommended choice due to its flexibility, ecosystem, and support for modern JavaScript, JSX, and TypeScript. Use JSLint only if you deliberately want a terse, opinionated tool with minimal configuration and accept its narrower ecosystem.
If you want, I can:
- generate an ESLint configuration that matches common JSLint rules,
- create a migration plan from JSLint to ESLint for your repo, or
- produce a recommended ESLint + Prettier setup for a specific stack (React, Node, TypeScript).