i have seen this code :
var myNet = require ("net");
and in some function:
function foo (x,y) {
var myNewNet = new myNet();
myNewNet.createServer(x,y);
}
why does the code above create a new object? what is the mechanism stands behind that?
one more question, how do i create a static var in node.js, for example a id number that has to be unique.
i came with this option for static variable:
var id =0;
and put it on the global scope, is it ok?
The require statement basically is like an import; it takes an external library and makes it available in your code.
ReplyDeleteIf you ever look in an external module, you will notice that it's just normal node.js js code. It has EXPORT statements in it. Those statements are what gets made available when you require something. Check out http://howtonode.org/creating-custom-modules
There is a GLOBAL keyword in node.js you can use to make something global
GLOBAL.IP_ADDRESS = "..."
As @Raynos says, it's not usually a good idea to do that, so another options is to export a constant from a module, so you can create a module and do
exports.STATIC_CONSTANT = "";
and then once you import the module you can do
var mod = require('mymodule');
mod.STATIC_CONSTANT;
EDIT, to answer you comment, the line
var myNet = require("net")
causes myNet to be whatever the net module exports. It must be exporting a function, so
var newNet = new myNet()
creates a new instance of the net object. From there
myNewNet.createServer()
is just invoking a method on the object you just created.