sjs-tutorial-oop.sjs

/*
 * Demonstrate an object-oriented style of programming. Declare a Person type 
 * and instantiate an instance. Convert that instance into a JSON node, for 
 * example to persist it to the database, and convert it back.
 */

// The Person constructor, e.g. var p = new Person(…)
Person = function(fname, lname) {
  if (fname) this.fname = fname;
  if (lname) this.lname = lname;
};

Person.prototype = {
  greet: function() { 
    return "Hi, I'm " + this.fname + " " + this.lname + "." 
  },
  toJSON: function() {
    return { fname: this.fname, lname: this.lname }
  }
};
// A static method that instantiates a new Person from JSON
Person.fromJSON = function(json) {
  var obj = json.valueOf ? json.valueOf() : json;
  var p = new Person(obj.fname, obj.lname);
  return p;
};

// Instantiate a new Person object
var sam = new Person("Sam", "Simon");
// Convert that object into a JSON node
var samNode = xdmp.toJSON(sam.toJSON());

// This is where you'd likely persist the sam document to the database
// xmdp.documentInsert("/sam.json", samNode, xdmp.defaultPermissions())
// (Don't forget to put a declareUpdate() at the top if you're doing this.)

// Re-hydrate a new Person person instance from the JSON node. Note
// the use of root to get the root node from the document node.
var s = Person.fromJSON(samNode.root);
// Verify that we indeed have a person and the fields have beeen properly 
// instantiated.
s instanceof Person
// Note that the === only evaluates to true on nodes that have been converted 
// to JavaScript objects (i.e. with node.valueOf()). == will do the expected 
// casting to a JavaScript object.
  && s.fname == "Sam"
// Make sure we've got our methods as well.
  && s.greet() === "Hi, I'm Sam Simon."