Javascript implementation methods

Constructor

 Function  Coder ()
{
  This  . Name  =     '  Modern magic  '  ;
  This  . Job  =     '  Web developers  ' ;
  This  . Coding  =     Function  ()
{
Alert (  '  I'm writingCode  '  );
}
}

  VaR  Coder  =     New Coder ();
Alert (CODER. Name );
Coder. coding (); 

Factory method

 Function  Createcoderfactory ()
{
  VaR  OBJ  =     New  Object ();
OBJ. Name  =     '  Modern magic  '  ;
OBJ. Job  =    '  ProgramEmployee  '  ;
OBJ. Coding  =     Function  ()
{
Alert (  '  I am writing code  '  );
};
  Return  OBJ;
}
  VaR Coder  =  Createcoderfactory ();
Alert (CODER. Name );
Coder. coding (); 

Both the factory method and constructor method share the same disadvantage, that is, every function of this class is instantiated every time an instance is created.

Prototype chain

 Function  Coder (){}
Coder. Prototype. Name  =     '  Modern magic  '  ;
Coder. Prototype. Job  =     ' Programmer  '  ;
Coder. Prototype. Coding  =     Function  (){
Alert (  '  I am writing code  '  );
};
  VaR  Coder  =     New Coder ();
Alert (CODER. Name );
Coder. coding (); 

The disadvantage of a prototype chain is that all its attributes are shared, and all other attributes of an instance will be changed as long as one instance changes. For example:

 

 VaR  Coder1  =     New  Coder ();
  VaR  Coder2  =     New  Coder ();
Alert (coder1.name );  /* Show modern magic  */  
Coder2.name  =     '  Nowamagic  '  ;
Alert (coder1.name );  /*  Show nowamagic  */  
Alert (coder2.name );  /*  This also shows nowamagic  */ 

Hybrid mode

The above three methods all have their own shortcomings, so we need to improve them.

 

 Function  Coder ()
{
  This  . Name  =     '  Modern magic  '  ;
  This  . Job  =     '  Programmer '  ;
}
Coder. Prototype. Coding  =     Function  (){
Alert (  '  I am writing code  '  );
}; 

Dynamic original chain

There is another way to solve the first three shortcomings.

 

 Function  Coder ()
{
  This  . Name =     '  Modern magic  '  ;
  This  . Job  =     '  Programmer  '  ;
  If  (  Typeof  (CODER. _ init) =     '  Undefined  '  )
{
  This  . Coding  =     Function  ()
{
Alert (  '  I am writing code  '  );
};
  This . _ Init  =     True  ;
}
}