What does the following javascript code mean? I guess it's defining a function within a function to make it look like OOP? Why the function can return multiple functions? what is the bracket at the end?
var grid_ui = function () {
function setup_data_source() {}
return {
init: function () {},
set_ds: function(rpt_headers, rpt_rows) {}
} // return
}();
The { } notation is called an object literal. It is same as:
a = new Object();
a.init = function() { };
a.set_ds = function(...) { };
return a;
and return { } returns an object.
The function () { ... }(); is a self-invoking function: it creates an anonymous function them immidiately invokes it.
In your code, the self-invoking function returns an object of functions, which is a namespace pattern. The value of grid_ui now contains { init: ..., set_ds: ... }, which is mentioned in return.
These concepts are very difficult to explain in one SO answer, so I will provide you some links:
it is defining an function then calling it and taking the return value and assigning it to grid_ui.
the value of grid_ui is now the object (also called a dictionary) containing the keys init and set_ds.
In javascript, you can define functions within functions and assign functions to variables.
Now you can make calls like grid_ui.init() and grid_ui.set_ds("test", 1).
It is OOP. Functions are objects in JavaScript.
This code means that there is a variable, grid_ui, which evaluates to an object that has two "public" functions, init and set_ds. init and set_ds also have a context which includes a "private" function, setup_data_source.
There are no brackets.
