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javascriptfunctionnativetokenkeyword

What does the 'native' keyword mean in JavaScript?

I stumbled upon a function called v8Locale in Chrome's Developer Console. I was curious so I entered the function to get the source code, and it revealed the following code:

function (a){
native function NativeJSLocale();
var b=NativeJSLocale(a);
this.locale=b.locale;
this.language=b.language;
this.script=b.script;
this.region=b.region;
}

I started searching on the Internet and found this file which seems to be the source (it looks like it has been minified though).

I have no idea what the native keyword means here. When I try to make something like this myself:

function bar() {}

function foo() {
    native function bar();
}

I get the following error message (as I expected, actually):

SyntaxError: Unexpected token native

How is it possible that the v8Locale function contains the native token, and what does it mean/do?

Solution

  • That is used to tell v8 that the function is implemented in C++ code