Code Formatting Guidelines @ t128n.dev

Consistent formatting removes noise from code review and keeps a codebase readable as it grows. These are the rules I’ve settled on across my projects, using oxfmt as the formatter.

Quick Start

import { defineConfig } from "oxfmt";
// https://t128n.dev/writing/code-formatting-guidelines
export default defineConfig({
  printWidth: 80,

  useTabs: true,
  tabWidth: 4,

  semi: true,
  singleQuote: false,
  trailingComma: "all",

  sortImports: {},
  sortPackageJson: {},
  sortTailwindcss: {},

  ignorePatterns: ["**/*.mdc", "content/**/*.md"],
});

Rules

Formatting

printWidth (integer, default 80): Soft line length limit. Lines exceeding this will be wrapped where possible.
semi (boolean, default true): Always add semicolons. Avoids ambiguous ASI edge cases.
singleQuote (boolean, default false): Use double quotes. Consistent with JSON and most framework conventions.
trailingComma (string): Add trailing commas wherever valid. Keeps diffs clean on multi-line additions.

Indentation

useTabs (boolean, default true): Indent with tabs. Allows each developer to set their own visual width.
tabWidth (integer, default 4): Visual width of a tab character. Has no effect on the emitted output.

Sorting

sortImports (object): Automatically sort import statements.
sortPackageJson (object): Automatically sort package.json keys.
sortTailwindcss (object): Automatically sort Tailwind CSS class names.

Ignored Paths

ignorePatterns (string[]): Paths excluded from formatting. Markdown content and MDC components are skipped to avoid interference with prose.