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What is the difference between different types of compilation in Dart?

sobes.tech AI

Answer from AI

Dart supports several compilation modes depending on the use case:

  1. AOT (Ahead-Of-Time) Compilation:

    • Used for creating native, high-performance applications for mobile (iOS, Android), desktop (Windows, macOS, Linux), and server platforms.
    • Code is compiled into machine code before execution.
    • Ensures fast startup and high performance.
    • Used when building release versions of applications (flutter build).
    • Does not support hot reload.

  2. JIT (Just-In-Time) Compilation:

    • Used during development for rapid iterative cycles.
    • Code is compiled into machine code at runtime.
    • Supports hot reload and hot restart with state preservation.
    • Provides quick feedback during development.
    • Used when running applications in debug mode (flutter run).
    • Less performant than AoT and has slower startup due to compilation during execution.

  3. Dart2js:

    • A compiler that converts Dart code into an optimized JavaScript file.
    • Used for creating web applications running in browsers.
    • Generates a large but highly optimized JS file.

  4. Dart Dev Compiler (DDC):

    • A fast incremental compiler that converts Dart code into JavaScript.
    • Used in web development for quick iteration and debugging in browsers.
    • Generates multiple JS files that are easier to debug but less optimized than Dart2js output.
    • Supports Source Maps for debugging original Dart code in browsers.

The main differences are summarized in the table:

Characteristic AoT Compilation JIT Compilation Dart2js Dart Dev Compiler (DDC)
Application Release (Mobile/Desktop) Development (Mobile/Desktop) Web (Release) Web (Development)
Compilation Time Before execution During execution Before execution Before execution
Startup Speed Fast Slower Depends on JS Fast
Performance High Lower High Lower
Output Size Optimized Code + Virtual Machine Optimized Multiple files
Hot Reload No Yes No Partial (WebDev)
Output Native machine code Machine code (JIT) JavaScript JavaScript

The choice of compilation mode depends on the target platform and the development stage (development or release).

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