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Re: Can somebody explain this to me

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From Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups comp.lang.javascript
Subject Re: Can somebody explain this to me
Date Tue, 06 Jan 2015 01:40:16 +0100
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Tony Johansson wrote:

> The code at the end works but I have a question.
> When I have this code construction with prototype I can call the getFoo in
> this way  var poo = f.getFoo(); // "bar"
>  P.prototype.getFoo = function ()
>        {

I recommend to put the opening brace of a function expression on the same 
line as the “function” keyword in order to tell function declarations and 
function expressions apart more easily.

>            return this.foo;
>        };
> 
> 
> I mean if I add this piece of code into the class definition

There are no classes in this case; prototype-based inheritance is used.

> I can call the getFoo in this way  var poo = f.getFoo(); // "bar"
                       ^ method

> this.getFoo = function ()
>            {
>                return this.foo;
>            };
> 
> So as a summary can somebody explain what is the advantage to use a
> prototype in this exemple?

Inherited methods can be reused.  In this example, one advantage is that 
only one Function instance is created, which saves memory as compared to the 
instance method approach.  It also saves runtime because the creation of 
that object only happens once.  (There are also disadvantages.)
 
>        function P(foo) //Here is the class definition

No, there is the declaration of a function named “P” that can be called as a 
constructor.  This also means that a Function instance (an object) is being 
created that can be referred to by “P”.

>        {
>            this.foo = foo;
>            // implicit return av "this" i den fall då P anropas som
> konstruktor

Correct.

>        var f = new P("bar");

Using the “new” keyword on a reference to an object that implements the 
internal [[Construct]] method (which applies to Function instances) calls 
that object as a constructor.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

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Thread

Can somebody explain this to me "Tony Johansson" <johansson.andersson@telia.com> - 2015-01-06 00:48 +0100
  Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-06 01:40 +0100
    Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-06 16:01 +0000
      Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-06 17:26 +0100
        Re: Can somebody explain this to me Joao Rodrigues <groups_jr-1@yahoo.com> - 2015-01-07 00:45 -0200
          Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-07 04:35 +0100
            Re: Can somebody explain this to me Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-01-07 16:15 -0200
              Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-07 21:20 +0100
                Re: Can somebody explain this to me "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-01-08 00:00 +0100
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 00:09 +0100
                Re: Can somebody explain this to me "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-01-08 10:53 +0100
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 16:17 +0100
                Re: Can somebody explain this to me "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-01-08 17:04 +0100
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 19:02 +0100
        Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-07 15:37 +0000
          Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-07 17:01 +0100
            Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-08 10:43 +0000
              Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-08 13:16 +0100
          Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 16:43 +0100
            Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-09 20:16 +0000
              Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-09 22:11 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-10 16:58 +0000
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-11 12:41 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-12 15:46 +0000
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-12 18:01 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-13 10:38 +0000
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-14 16:06 +0000
              Re: Can somebody explain this to me Scott Sauyet <scott.sauyet@gmail.com> - 2015-01-21 13:00 -0800
                Re: Can somebody explain this to me Joao Rodrigues <groups_jr-1@yahoo.com> - 2015-01-21 20:53 -0200
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-22 11:43 +0000
                Re: Can somebody explain this to me Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-01-22 10:20 -0200
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-23 19:42 +0000
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-28 18:14 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-22 11:39 +0000
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-22 13:27 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-23 14:36 +0000
                Re: Can somebody explain this to me Scott Sauyet <scott.sauyet@gmail.com> - 2015-01-23 08:51 -0800
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-23 23:17 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-24 16:42 +0000
                Re: Can somebody explain this to me Scott Sauyet <scott.sauyet@gmail.com> - 2015-01-24 15:35 -0800
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-25 11:08 +0000
                Re: Can somebody explain this to me "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2015-01-26 08:33 -0800
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-27 14:10 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-28 15:50 +0000
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-28 18:26 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-29 10:29 +0000
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-31 00:37 +0100
                Re: Can somebody explain this to me "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2015-01-28 13:30 -0800
                Re: Can somebody explain this to me "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-01-28 22:40 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-29 10:32 +0000
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-29 10:23 +0000
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-29 11:04 +0000
                Re: Can somebody explain this to me "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2015-01-26 08:21 -0800
                Re: Can somebody explain this to me Scott Sauyet <scott.sauyet@gmail.com> - 2015-01-26 11:10 -0800
                Re: Can somebody explain this to me Scott Sauyet <scott.sauyet@gmail.com> - 2015-01-22 06:36 -0800
      Re: Can somebody explain this to me Tim Streater <timstreater@greenbee.net> - 2015-01-06 17:34 +0000
        Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-06 19:03 +0100
          Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-07 15:07 +0000
            Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-07 16:41 +0100
              Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-07 17:22 +0100
                Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-08 10:36 +0000
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-08 13:36 +0100
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 17:54 +0100
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-08 19:48 +0100
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 22:09 +0100
                Re: Can somebody explain this to me Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2015-01-08 18:22 -0200
                Re: Can somebody explain this to me "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-01-08 22:13 +0100
                Re: Can somebody explain this to me Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-01-08 22:25 +0100
              Re: Can somebody explain this to me John Harris <niam@jghnorth.org.uk.invalid> - 2015-01-08 10:25 +0000
                Re: Can somebody explain this to me "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2015-01-08 11:33 +0100

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