数値や文字列をラップしたValueクラスを作るサンプル

value-object-example.js

function Length(value, uom) {
  this.value = value;
  this.uom = uom || "cm";
}

function Square(length, uom) {
  this.length = new Length(length, uom);
}

function Colored(figure, r, g, b) {
  this.__proto__ = figure;
  this.color = {r: r||0, g: g||0, b: b||0};
}

var square = new Square(150, 'cm');
var colored_square = new Colored(square, 127, 0, 0);
colored_square.length.value = 1.5;   // !!!
colored_square.length.uom   = 'm';   // !!!
colored_square.color.r      = 127;