Babel vs Closure Compiler: What are the differences?

Introduction

Babel and Closure Compiler are both popular tools used in web development. However, there are key differences between them that make each of them suitable for different scenarios.

1. Babel: Babel is a JavaScript compiler that allows developers to write code in the latest version of JavaScript and converts it into backward-compatible versions for older browsers. It focuses on code transformation and is primarily used for language features and syntax enhancements.

2. Closure Compiler: Closure Compiler, on the other hand, is a JavaScript optimizer, transpiler, and minifier. It not only compiles the code into an older version, but also performs advanced code optimizations to make the resulting code smaller, faster, and more efficient. It focuses on code optimization and is primarily used for performance enhancements.

3. Output Size: Babel's primary goal is to enable the use of modern JavaScript features, so the resulting output is often larger as it includes the necessary polyfills and transformations. Closure Compiler, on the other hand, performs aggressive code optimizations, resulting in a smaller output size.

4. Runtime Performance: Babel does not optimize code for better runtime performance, as its main focus is on language features and syntax. Closure Compiler, however, applies various advanced optimizations, such as dead code elimination and code inlining, to improve runtime performance.

5. Type Checking: Babel does not perform any type checking itself. It relies on type annotations provided by external tools like TypeScript or Flow. Closure Compiler, on the other hand, has its own built-in type checking system that helps catch type errors and provides benefits like better optimizations based on type information.

6. Modularity: Babel operates on a per-file basis and can be used as a standalone tool in a modular fashion. Developers can choose specific plugins or presets to customize the transformation process. Closure Compiler, on the other hand, typically works on an entire codebase and requires a more comprehensive configuration. It performs global optimizations that may require understanding the entire codebase.

In Summary, Babel focuses on language features and syntax transformations, while Closure Compiler emphasizes code optimization, resulting in smaller output size and improved runtime performance.