JavaScript_Succinctly

sample, we take the classic Person object and mimic the pattern that JavaScript uses
for inheritance.
Sample: sample130.html
var Person = function () { };
// All Person instances inherit the legs, arms, and countLimbs
properties.
Person.prototype.legs = 2;
Person.prototype.arms = 2;
Person.prototype.countLimbs = function () { return this.legs + this.arms;
};
var chuck = new Person();
console.log(chuck.countLimbs()); // Logs 4.
In this code, a Person() constructor function is created. We then add properties to the
prototype property of Person(), which can be inherited by all instances. Clearly, you
can leverage the prototype chain in your code the same way that JavaScript leverages it
for native object inheritance.
As a good example of how you might leverage this, you can create a constructor
function whose instances inherit the legs and arms properties if they are not provided
as parameters. In the following sample, if the Person() constructor is sent parameters,
the parameters are used as instance properties, but if one or more parameters are not
provided, there is a fallback. These instance properties then shadow or mask the
inherited properties, giving you the best of both worlds.
Sample: sample131.html
var Person = function (legs, arms) {
// Shadow prototype value.
if (legs !== undefined) { this.legs = legs; }
if (arms !== undefined) { this.arms = arms; }
};
};
Person.prototype.legs = 2;
Person.prototype.arms = 2;
Person.prototype.countLimbs = function () { return this.legs + this.arms;
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