What You Actually Need From a JavaScript Style Guide
A Style Guide For JavaScript Cheat Sheet isn't a magical document that will make your codebase look professional overnight. It's a reference you'll consult when someone on your team insists on using single quotes instead of double quotes, or when a junior dev adds semicolons inconsistently across files and you need to explain why that matters without going on a thirty-minute tangent. I've built enough projects to know that consistency beats creativity in production codebases every single time. Most solid JavaScript style guides converge on a handful of non-negotiable rules. Use let and const instead of var. Prefer arrow functions for callbacks and anonymous functions. Stick to double quotes for strings unless you're working in a codebase that standardized on single quotes. Never mix them within the same file. Use two-space indentation, not tabs, because tabs cause rendering issues across different editors and terminals and people still argue about this in 2024. Always include semicolons even though JavaScript has automatic semicolon insertion. ASI is a trap. It works until it doesn't, and when it fails, the error message points to a line hundreds of characters away from where the actual problem is. I learned this the hard way on a React project where a missing semicolon before a parenthesis triggered a syntax error that took me forty-five minutes to trace back to a statement on the previous line. For naming conventions, use camelCase for variables and functions, PascalCase for classes and components, UPPER_SNAKE_CASE for constants that truly are constant. Prefix private methods with an underscore only if your team agrees on that pattern. Don't create your own personal convention mid-project because everyone else will have to adapt to it and resentment builds quietly over time.
Async code should use async/await syntax consistently. Avoid mixing Promise.then chains with async/await in the same file. It's not harder to read, it's objectively harder to read because your brain has to switch between two mental models. Pick one approach per module and stick with it.
How to Actually Use This Stuff in a Real Codebase
Writing the guide is the easy part. Getting people to follow it is where most teams fail. I once spent three weeks trying to enforce a style guide on a team of six developers who had been writing JavaScript their own way for years. The turning point wasn't a meeting or an email. It was adding ESLint with the Airbnb config and formatting rules to their CI pipeline. After the first failed build, nobody questioned it anymore. The machine enforced the rules and humans stopped debating them. Don't try to customize your style guide to include every preference your team has. That turns a ten-page document into a fifty-page document that nobody reads. Pick the mainstream standard for your ecosystem. If you're doing Node.js, go ESLint with standard or Airbnb. If you're doing React, follow the React style guide as a supplement. If you're doing TypeScript, extend your existing JavaScript config with the TypeScript-specific rules. Layering doesn't compound nicely. It compounds conflicts.
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The Counter-Intuitive Parts Nobody Talks About
Here's something most style guides omit: shorter function names are fine when the context makes them unambiguous. If you're inside a UsersComponent that filters and sorts user lists, a function called mapUsers() is preferable to mapAllActiveUsersToDisplayObjects(). The style guide isn't about being verbose. It's about being predictably clear. Overly long names are just as bad as cryptic ones. Another thing: don't treat style guides as comprehensive coding standards. A style guide covers formatting and syntax conventions. It doesn't cover architecture, state management patterns, testing strategies, or performance optimization. When teams conflate style with substance, they end up with beautifully formatted code that has fundamental design problems. Keep the scope tight. A style guide that's eight to fifteen pages is about right. Anything longer means you're trying to solve problems the guide can't actually solve.
Where Style Guides Fall Short
The blunt truth is that a style guide cannot fix a team that doesn't care about code quality. I've seen Style Guide For JavaScript Cheat Sheet documents pinned to wikis and shared in Slack channels with zero enforcement and zero impact. The tooling has to do the enforcing. ESLint, Prettier, editorconfig, and pre-commit hooks matter more than the document itself. Without tooling, a style guide is just an opinion piece that lives on a server somewhere. Another limitation: style guides become outdated quickly. New JavaScript features ship every year. Arrow functions were controversial five years ago. Optional chaining was considered experimental three years ago. If your guide was written in 2019 and nobody has updated it, it's actively harmful because it's telling people to avoid patterns that are now standard. Audit your style guide at least once a year and remove anything that references deprecated practices. And here's the uncomfortable part: strict adherence to any style guide can slow down rapid prototyping. If you're building an internal tool that will be used for three months and then discarded, spending an hour configuring linting rules and formatting is probably not worth it. Save the discipline for code that lives longer than the sprint it was written in. Knowing when to skip the style guide is itself a kind of expertise.
What to Include When You're Building One
Start with the formatting basics: indentation, line length (100 characters is reasonable, 80 is excessive for modern screens, 120 is too loose), quote style, semicolons, trailing commas in objects and arrays. Then move to naming conventions. Then async/await rules. Then import ordering. Then anything specific to your framework or project constraints. Everything else belongs in a separate architecture or best-practices document, not in the style guide. If you want a starting point, the ESLint recommended config combined with Prettier covers about ninety percent of what most teams need. The remaining ten percent is usually project-specific and should be documented in your repository's README rather than in a standalone guide. That keeps the information where developers actually look for it.
Downloading a Reference
Most teams don't need to write their own style guide from scratch. The npm ecosystem has well-maintained configs that serve as de facto standards. eslint-config-airbnb, eslint-config-standard, and prettier's default settings will get you nine-tenths of the way there. For a printable reference, many senior developers export their configured ESLint rules as a PDF or a markdown file stored in the project root. That's more useful than a generic cheat sheet found on the internet because it reflects the actual rules your codebase enforces. When someone asks why their code won't merge, you point them to the file that already exists in the repo instead of a third-party link that might rot in six months. I keep a single config file in each project that maps directly to the style expectations. It's one JSON file, it changes infrequently, and it's version-controlled alongside the code. That's the closest thing to a cheat sheet that actually gets used. Everything else is noise.
