What is 'define' used for in JavaScript (a

问题:

I have searched high and low for documentation on this, but I just cannot find anything anywhere.

I am using Aloha and want to use their sidebar prototype to create a new side bar of my own attached to other plugin functionality.

Their sidebar.js starts off with this, but I can't for the life of me find any documentation that explains what it means.

define( [
    'aloha/core',
    'aloha/jquery',
    'aloha/selection'
], function (Aloha, jQuery, Selection, Plugin) {

It then goes on in that wrapper to define a bunch of functions, so vars and some proptotypes- which I can just about get my head around...

What is that saying or where can I find an explanation?

回答1:

I can't say for sure without seeing the entire script, but it's likely to be the define function from RequireJS, in particular the "define with dependencies" form of that function. It is used to define a "module":

A module is different from a traditional script file in that it defines a well-scoped object that avoids polluting the global namespace. It can explicitly list its dependencies and get a handle on those dependencies without needing to refer to global objects, but instead receive the dependencies as arguments to the function that defines the module.

And the "define with dependencies" form of define is described as follows:

If the module has dependencies, the first argument should be an array of dependency names, and the second argument should be a definition function. The function will be called to define the module once all dependencies have loaded. The function should return an object that defines the module.