Modules
The two key concepts you need to be aware of here are the idea of a define method for facilitating module definition and a require method for handling dependency loading. define is used to define named or unnamed modules based on the proposal using the following signature:
define(
module_id /*optional*/,
[dependencies] /*optional*/,
definition function /*function for instantiating the module or object*/
);
As you can tell by the inline comments, the module_id is an optional argument which is typically only required when non-AMD concatenation tools are being used (there may be some other edge cases where it's useful too). When this argument is left out, we call the module anonymous.
When working with anonymous modules, the idea of a module's identity is DRY, making it trivial to avoid duplication of filenames and code. Because the code is more portable, it can be easily moved to other locations (or around the file-system) without needing to alter the code itself or change its ID. The module_id is equivalent to folder paths in simple packages and when not used in packages. Developers can also run the same code on multiple environments just by using an AMD optimizer that works with a CommonJS environment such as r.js.
Back to the define signature, the dependencies argument represents an array of dependencies which are required by the module you are defining and the third argument ('definition function') is a function that's executed to instantiate your module. A barebone module could be defined as follows:
// A module_id (myModule) is used here for demonstration purposes only
define('myModule',
['foo', 'bar'],
// module definition function
// dependencies (foo and bar) are mapped to function parameters
function ( foo, bar ) {
// return a value that defines the module export
// (i.e the functionality we want to expose for consumption)
// create your module here
var myModule = {
doStuff:function(){
console.log('Yay! Stuff');
}
}
return myModule;
});
// An alternative example could be..
define('myModule',
['math', 'graph'],
function ( math, graph ) {
// Note that this is a slightly different pattern
// With AMD, it's possible to define modules in a few
// different ways due as it's relatively flexible with
// certain aspects of the syntax
return {
plot: function(x, y){
return graph.drawPie(math.randomGrid(x,y));
}
}
};
});
require on the other hand is typically used to load code in a top-level JavaScript file or within a module should you wish to dynamically fetch dependencies.
// Consider 'foo' and 'bar' are two external modules
// In this example, the 'exports' from the two modules loaded are passed as
// function arguments to the callback (foo and bar)
// so that they can similarly be accessed
require(['foo', 'bar'], function ( foo, bar ) {
// rest of your code here
foo.doSomething();
});
hoping this is helpfull for you...
