Code Formatting & Linting (Formatter & Linter)

In large codebases, Prettier and ESLint often slow down developer loops and CI pipelines due to substantial bootstrap and memory overhead. Amber integrates a high-performance formatter and linter driven by OXC (The JavaScript Oxidation Compiler) written in Rust.

1. Code Formatting (amber fmt)

amber fmt formats JavaScript, TypeScript, JSX, and TSX files orders of magnitude faster than conventional tools.

1.1 Basic Usage

# Format a single file
$ amber fmt src/index.ts

# Format an entire directory recursively
$ amber fmt src/

# Format multiple paths
$ amber fmt src/ tests/ examples/

1.2 CI Check Mode (--check)

In CI workflows, use --check to verify code conformance without modifying files on disk:

$ amber fmt src/ --check

Example output:

🔍 Checking formatting for 24 files...
Formatted 24 files in 4.2ms (100% compliant)

2. Static Code Linting (amber lint)

amber lint analyzes AST structures and catches hazardous patterns out of the box without complex configuration files.

2.1 Running the Linter

$ amber lint src/

When violations are detected, amber lint prints formatted diagnostics with line numbers and recommendations:

🚨 Lint issue in src/auth.ts:18:5
  18 |     eval(userPayload);
     |     ^^^^ no-eval: eval() is unsafe and prohibited in Amber secure runtime.

Summary: 1 error, 0 warnings found in 18 files (checked in 3.1ms).

2.2 Built-in Core Rules

• no-eval: Forbids dangerous dynamic eval() execution;
• no-debugger: Detects leftover debugging statements;
• no-empty: Catches empty conditional or catch blocks;
• no-dupe-keys: Disallows duplicate keys in object literals;
• syntax-error: Rigorous syntax validation for TS/JS files.

3. Performance Benchmark

Benchmarked on a 10,000-line TypeScript codebase: