Is JavaScript interpreted or compiled language?

What is an interpreted language?

• These languages are executed line by line, with the interpreter reading and executing the code directly.

• Pros:

  • Quick to start executing code.

  • Easier to debug due to immediate feedback.

• Cons:

  • Slower execution compared to compiled languages because of line-by-line interpretation.

• Example: Python, Ruby.

What is compiled language?

• These languages undergo a process called compilation, where they are translated into machine code (binary code).

• Pros:

  • Faster execution because the code is pre-compiled into machine code.

• Cons:

  • Longer initial compilation time.

  • Debugging can be more complex.

• Example: C, C++

JavaScript, the language of the web, doesn’t neatly fit into either category. It combines elements of both interpretation and compilation:

1. Interpreter for Initial Execution:

   • When you run a JavaScript script, an interpreter steps in. It swiftly executes the code, allowing for immediate feedback.

   • This agility is particularly useful during development and debugging phases.

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

   • JavaScript engines, like the popular V8 engine, employ JIT compilation.

   • JIT compilation dynamically translates JavaScript code into optimized machine code just before execution.

   • Frequently executed code paths receive special attention, resulting in improved performance.

JavaScript bridges the gap between interpreted and compiled languages, offering the best of both worlds. As a web developer, understanding these nuances helps you write efficient and maintainable code.