Question about the compiler

[italoacasas]

Hi Guys, I'know maybe this it is not the correct place tu put this question but I don't find a good place anywhere.

Why JavaScript is not a interpreter language?
Why JavaScript is a "compiler" language?

[getify]

This is not really a support forum, but briefly...

JS has to be processed (aka "compiled") first before execution because some of the language mechanics require early errors (that is, compile-time errors) if certain conditions are found in the code, such as:

"use strict";
function foo( x, x ) { .. }  // duplicate param name not allowed in strict mode

Some syntax errors technically could be caught if the code only went through a quick tokenization scan (not full parsing/compilation), but other situations like that one above require actually understanding the structure of the program to know if something is valid or not.

[getify]

This is not really a support forum, but briefly...

JS has to be processed (aka "compiled") first before execution because some of the language mechanics require early errors (that is, compile-time errors) if certain conditions are found in the code, such as:

"use strict";
function foo( x, x ) { .. }  // duplicate param name not allowed in strict mode

Some syntax errors technically could be caught if the code only went through a quick tokenization scan (not full parsing/compilation), but other situations like that one above require actually understanding the structure of the program to know if something is valid or not.

[ljharb]

The words "compiled" and "interpreted" technically refer to implementations, and as such, every single language could be compiled or interpreted.

However, the way they're most commonly used, I would classify JS as an interpreted language (not compiled), and C++ as a compiled language, for example.

It really just depends on how pedantic you want to be about the definitions - if you stick with the most precise definition, no language is either, only an implementation is one or the other.

[ljharb]

The words "compiled" and "interpreted" technically refer to implementations, and as such, every single language could be compiled or interpreted.

However, the way they're most commonly used, I would classify JS as an interpreted language (not compiled), and C++ as a compiled language, for example.

It really just depends on how pedantic you want to be about the definitions - if you stick with the most precise definition, no language is either, only an implementation is one or the other.