Code Formatting

/**
 * Prettier formatter function with configuration discovery
 * @param argv - Command line arguments including files and options
 * @param options - Execution options for dry run and process control
 * @returns ChildProcess when executed, string when dry run
 */
function prettier(argv: string[], options?: RunOptions): ChildProcess | string;

# Format files
lb-prettier "**/*.ts" "**/*.js"

# Check formatting without changes
lb-prettier --check "**/*.ts"

# List files that would be formatted
lb-prettier --list-different "**/*.ts"

# Write formatted files
lb-prettier --write "**/*.ts" "**/*.js"

# Format specific files
lb-prettier src/index.ts src/utils.ts

import { prettier } from "@loopback/build";

// Format TypeScript files
const child = prettier(["--write", "**/*.ts"]);

// Dry run to see command
const command = prettier(["--check", "src/"], { dryRun: true });
console.log(command); // Shows the Prettier command that would be executed

// Format with custom working directory
prettier(["--write", "src/"], { cwd: "/path/to/project" });

// @loopback/build/config/.prettierrc contents:
interface PrettierConfig {
  bracketSpacing: false;    // {foo} instead of { foo }
  singleQuote: true;        // 'string' instead of "string"
  printWidth: 80;           // Line wrap at 80 characters
  trailingComma: "all";     // Trailing commas everywhere
  arrowParens: "avoid";     // x => x instead of (x) => x
}

// Glob patterns for multiple files
// Specific file paths
// Supports all file types that Prettier handles

# TypeScript and JavaScript
lb-prettier "**/*.{ts,js}"

# All supported formats
lb-prettier "**/*.{ts,js,json,md,yml,yaml}"

# Specific directories
lb-prettier "src/**/*.ts" "test/**/*.ts"

interface PrettierOptions {
  "--write": boolean;              // Write formatted files to disk
  "--check": boolean;              // Check if files are formatted
  "--list-different": boolean;     // List files that differ from Prettier formatting
  "--config": string;              // Path to configuration file
  "--no-config": boolean;          // Do not look for configuration file
  "--find-config-path": string;    // Find and return path to configuration file
  "--ignore-path": string;         // Path to ignore file
  "--no-ignore": boolean;          // Do not look for ignore files
  "--with-node-modules": boolean;  // Process files in node_modules
  "--parser": string;              // Parser to use (auto-detected by default)
  "--print-width": number;         // Line wrap width
  "--tab-width": number;           // Tab width
  "--use-tabs": boolean;           // Use tabs instead of spaces
  "--semi": boolean;               // Print semicolons
  "--single-quote": boolean;       // Use single quotes
  "--quote-props": string;         // Quote object properties
  "--jsx-single-quote": boolean;   // Use single quotes in JSX
  "--trailing-comma": string;      // Trailing comma policy
  "--bracket-spacing": boolean;    // Print spaces inside object brackets
  "--bracket-same-line": boolean;  // Put closing bracket on same line
  "--arrow-parens": string;        // Arrow function parentheses policy
  "--range-start": number;         // Format from this character
  "--range-end": number;           // Format to this character
  "--stdin-filepath": string;      // File path for stdin input
  "--end-of-line": string;         // Line ending style
}

import { prettier } from "@loopback/build";

// Format all TypeScript files
prettier(["--write", "**/*.ts"], { dryRun: false });

// Check formatting without changes
prettier(["--check", "src/"], { dryRun: false });

{
  "scripts": {
    "prettier:cli": "lb-prettier \"**/*.ts\" \"**/*.js\"",
    "prettier:check": "npm run prettier:cli -- --list-different",
    "prettier:fix": "npm run prettier:cli -- --write",
    "format": "npm run prettier:fix"
  }
}

# Use custom config file
lb-prettier --config .prettierrc.custom.json --write "**/*.ts"

# Ignore configuration files
lb-prettier --no-config --write --single-quote "**/*.ts"

# Custom ignore file
lb-prettier --ignore-path .prettierignore.custom --write "**/*.ts"

// Syntax errors in files are reported with file location
// Configuration errors show helpful error messages  
// Process exits with non-zero code on formatting errors (when using --check)
// Invalid file patterns are reported clearly