这是什么类型的声明？ 功能？ 类？

Question

I was looking at code in node.js, express, mongoose. It is defining a schema:

var Comment = new Schema({
    username : String,
    content  : String,
    created  : Date
});

I do not understand what this actaully is, because

var Comment = 

Is like a function/variable

new Schema

is like a class and

    {
        username : String,
        content  : String,
        created  : Date
    }

is like an associative array...

What exactly is this type of block? and how does it work?

Thanks a lot

Answer 1

This is the object-oriented style of JavaScript, especially the concept of model-view controller.

What you describe in your examples here is called a model. It defines how the data which are put in and out fit into the concept.

So this model would be named comment and it would hold username, content as strings and created as date. It would be easily saveable to a database later by calling eg

Comment.save();

"new Schema" tells the engine here that a new model should be created.

Please see also here: http://mongoosejs.com/docs/guide.html