// I represent a friend.

function Friend( name, age ) {

    // Store properties.

    var firstName = getFirstName( name );

    // Return the public API to the component.

    return({

        sayHello: sayHello

    });

    // ---

    // PUBLIC METHODS.

    // ---

    // I return a greeting.

    function sayHello() {

        return( "Hello, I am " + firstName + "; I am " + age + "." );

    }

    // ---

    // PRIVATE METHODS.

    // ---

    // I get the first name, delimited by white-space characters.

    function getFirstName( fullName ) {

        return( fullName.split( " " )[ 0 ] );

    }

}

​

​

​

a = new Friend('Abe', 20);

b = new Friend('Burt', 30);

​

console.log('strict equality', a.sayHello === b.sayHello);

console.log('loose equality', a.sayHello == b.sayHello);

console.log('instance checking', (a instanceof Friend));

​

​

//=================

​

var protoFriend = function( name, age ) {

  this.firstName = this.getFirstName( name );

  this.age = age;

};

protoFriend.prototype = {

  getFirstName: function( fullName ) {

    return( fullName.split( " " )[ 0 ] );

  },

  sayHello: function() {

    return( "Hello, I am " + this.firstName + "; I am " + this.age + "." );

  }

};

​

pa = new protoFriend('Abe');

pb = new protoFriend('Burt');

​

console.log('strict equality', pa.sayHello === pb.sayHello);

console.log('loose equality', pa.sayHello == pb.sayHello);

console.log('instance checking', (pa instanceof protoFriend));