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Learn whether JavaScript is compiled or interpreted, and the benefits and drawbacks of each approach.
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What is JavaScript?
JavaScript is a high-level, interpreted programming language. It is a language which is also characterized as dynamic, weakly typed, prototype-based and multi-paradigm.
What is a Compiled Language?
A compiled language is a programming language that needs to be processed by a compiler before it can be run. The compiler transforms the code written in the source language into another form called machine code, which can be run on a computer.
JavaScript is not a compiled language, but it is interpreted. This means that it is not transformed into machine code before it is run, but the code is executed line by line by an interpreter.
What is Just-In-Time Compilation?
Just-in-time (JIT) compilation is a form of compilation where code is only compiled as it is about to be executed, rather than ahead of time. This can provide a significant performance boost as it means that code only needs to be compiled once, when it is first executed, rather than ahead of time.
JIT compilation is often used in dynamic languages such as JavaScript, where the code that needs to be executed can vary at runtime. It can also be used in Ahead-of-time (AOT) compiled languages such as Java, where the JIT compiler can compile code that hasn’t been previously compiled.
It’s important to note that JIT compilation is different from interpreted execution, where code is not compiled at all, but simply parsed and executed on the fly. In contrast, with JIT compilation the code is still compiled, but it’s only compiled as it’s about to be executed.
What are the Advantages and Disadvantages of JavaScript?
JavaScript is a high-level, interpreted programming language. It is a language which is also characterized as dynamic, weakly typed, prototype-based and multi-paradigm. JavaScript was created in order to make webpages more interactive. More interactivity meant that webpages were becoming more like applications, and the methods used to create them were beginning to resemble those used to create software programs.
Is JavaScript Compiled?
JavaScript is not compiled in the traditional sense. That is, there is no program that you can run that will take your JavaScript code and turn it into machine code that can run on a computer.
Instead, JavaScript code is interpreted by the JavaScript engine in the browser. The engine takes each line of code one at a time and runs it. It then takes the next line of code and runs it. It continues doing this until it reaches the end of the code or encounters an error.
This interpretation process can be slow, especially if the code is large or complex. However, modern browsers have optimizations in place to make JavaScript execution as fast as possible. And, more importantly, developers can use tools to write code that runs more efficiently on browsers’ JavaScript engines.
