You Don't Know JS: this & Object Prototypes
Publisher: O'Reilly Media
Final Release Date: July 2014
Pages: 174

No matter how much experience you have with JavaScript, odds are you don’t fully understand the language. This concise, in-depth guide takes you inside JavaScript’s this structure and object prototypes. You’ll learn how they work and why they’re integral to behavior delegation—a design pattern in which objects are linked, rather than cloned.

Like other books in the “You Don’t Know JS” series, this and Object Prototypes dives into trickier parts of the language that many JavaScript programmers simply avoid. Armed with this knowledge, you can become a true JavaScript master.

With this book you will:

  • Explore how the this binding points to objects based on how the function is called
  • Look into the nature of JS objects and why you’d need to point to them
  • Learn how developers use the mixin pattern to fake classes in JS
  • Examine how JS’s prototype mechanism forms links between objects
  • Learn how to move from class/inheritance design to behavior delegation
  • Understand how the OLOO (objects-linked-to-other-objects) coding style naturally implements behavior delegation
Table of Contents
Product Details
About the Author
Recommended for You
Customer Reviews

REVIEW SNAPSHOT®

by PowerReviews
oreillyYou Don't Know JS: this & Object Prototypes
 
4.7

(based on 14 reviews)

Ratings Distribution

  • 5 Stars

     

    (12)

  • 4 Stars

     

    (1)

  • 3 Stars

     

    (0)

  • 2 Stars

     

    (1)

  • 1 Stars

     

    (0)

93%

of respondents would recommend this to a friend.

Pros

  • Well-written (10)
  • Accurate (8)
  • Concise (8)
  • Easy to understand (7)
  • Helpful examples (7)

Cons

No Cons

Best Uses

  • Intermediate (11)
  • Expert (6)
  • Student (5)
  • Novice (4)
    • Reviewer Profile:
    • Developer (11)

Reviewed by 14 customers

Displaying reviews 1-10

Back to top

Previous | Next »

 
5.0

The most useful title in the series so far

By Geronimus

from Toronto, Canada

About Me Developer

Pros

  • Accurate
  • Concise

Cons

  • Casual American Idioms

Best Uses

  • Expert
  • Intermediate
  • Student

Comments about oreilly You Don't Know JS: this & Object Prototypes:

Addressed to those who frequently rely on third-party libraries to mediate their interface with JavaScript, the author goes into the gritty details of how the premiere web language actually works under the hood, with loads of examples of unusual behaviour, and gotchas.

I've found this to be the most useful volume of the series, explaining in eye-watering detail the sometimes baffling behaviour of the "this" keyword, and making a persuasive case for using the object prototype system as it was intended, rather than shoe-horning in mental models from Java and other "class-oriented" languages.

 
5.0

Great if you want to take your js to the next level

By Garvin

from Washington, DC

Verified Reviewer

Comments about oreilly You Don't Know JS: this & Object Prototypes:

This book was great for me because I had done quite a bit of js over the years but never quite understood the inner workings of the prototype system. I definitely have a better understanding after reading the book.

(1 of 1 customers found this review helpful)

 
5.0

This is THE JS book

By Arul

from India

Verified Reviewer

Pros

  • Accurate
  • Easy to understand
  • Well-written

Cons

    Best Uses

      Comments about oreilly You Don't Know JS: this & Object Prototypes:

      Makes lot of sense and everything clear

      (2 of 3 customers found this review helpful)

       
      5.0

      So happy to know much more... now!

      By laruiss

      from Paris, France

      About Me Developer

      Verified Buyer

      Pros

      • Accurate
      • Concise
      • Easy to understand
      • Helpful examples
      • Well-written

      Cons

        Best Uses

        • Expert
        • Intermediate

        Comments about oreilly You Don't Know JS: this & Object Prototypes:

        Really easy to read, just as in the first book (Scope & Closures), and pleasant to be taught quite complicated concepts with simplicity (and talent). I will surely buy the next one in the series... Ooops, already did!

        (4 of 4 customers found this review helpful)

         
        5.0

        More than just a javascript book...

        By The Gayngler

        from New York, NY

        About Me Developer

        Verified Buyer

        Pros

        • Accurate
        • Concise
        • Easy to understand
        • Helpful examples
        • Well-written

        Cons

          Best Uses

          • Expert
          • Intermediate
          • Novice
          • Student

          Comments about oreilly You Don't Know JS: this & Object Prototypes:

          'this and Object prototypes' is the second book in the 'You Don't know Javascript' book series. I would argue that this book probably could've served as the first book becuase this book challenges developers to actually re-consider the need of and use of the classical design patterns and assessing the benefits and drawbacks of it. In other words it challenges developers to actually be engineers instead of just developers.

          It is my opinion that I and other developers have been lazy in that we just accept classical software design as the way software should be developed without really thinking about what that actually means and the benefits and drawbacks of classical design patterns. Rather than fully embracing the benefit of behavior based delegation-oriented design in Javascript, developers have typically shoe-horned in the classical design patterns into Javascript.

          If you were even mildly disappointed in the first book in this series 'Scope and Closures', you will pleased to know that this book is head and shoulders better than the first book in this series and really is a shining example of what a good programming book should do is challenge you to think about software design in ways you had not previously really given much thought to.

          Gone is the somewhat pretentious tone of the previous book. Instead the author takes a different tone as he aims to teach developers think about the implications of classical and behavioral design patterns. It is as if Kyle got better at writing a book that people can read and learn from. There are plenty of code examples along with detailed explanations of what Javascript is actually doing behind the scenes. This may actually just be a good computer science book to have in general. I am very happy with what I have learned from this book.

          The last three chapters that compare classical vs behavior based design patterns in javascript really is worth the price of this book. This book is very well written and I think the last three chapters of this book has uses as a computer science topic in general and should not be limited to just a discussion about Javascript hence the 5 out of 5 stars I a giving it.

          (1 of 1 customers found this review helpful)

           
          4.0

          well to fill gaps

          By Laurent

          from Bordeaux

          About Me Developer

          Verified Buyer

          Pros

          • Easy to understand
          • Well-written

          Cons

            Best Uses

            • Intermediate

            Comments about oreilly You Don't Know JS: this & Object Prototypes:

            With this book, I have learned two things that I didn't understand in Js :
            - heritage whith prototype
            - this keyword

            (0 of 1 customers found this review helpful)

             
            5.0

            totally worth ur time and money

            By mihneasim

            from EU

            About Me Developer

            Verified Buyer

            Pros

            • Easy to understand
            • Helpful examples

            Cons

              Best Uses

              • Intermediate
              • Novice
              • Student

              Comments about oreilly You Don't Know JS: this & Object Prototypes:

              I like his explanations. Suitable for any js apprentice.

              (2 of 2 customers found this review helpful)

               
              5.0

              Excellent coverage of a complex topic

              By Matthew

              from Des Moines, IA

              Verified Reviewer

              Pros

              • Concise
              • Helpful examples
              • Well-written

              Cons

              • Difficult to understand

              Best Uses

              • Expert
              • Intermediate

              Comments about oreilly You Don't Know JS: this & Object Prototypes:

              Kyle Simpson explains the semantics of using "this" in Javascript and why it is not the same as Java. The Javascript keyword "this" is often misunderstood. Many works treat it as the Javascript equivalent of Java's "this" or Python's "self," and while that understanding will lead to working programs in most cases, Simpson explains where that conception will break down in a way that many programmers will not be able to anticipate. He later discusses Javascript's prototypal inheritance and how it works different than typical inheritance designs.

              This text should not be a first introduction to the language and maybe not even a second or third. The topics covered are quite advanced and require a relatively high familiarity with Javascript to begin to understand. At times the text can be very confusing and require re-reading sections to fully grasp, however this is due to the complexity of the material covered and not due the author. The author's writing style is quite clear and his examples are well explained. Code samples are very short and to the point, not wasting space with unnecessary filler code which so many technical books do (pages of GUI code for explaining a simple input/output example for instance).

              This is the first example I have seen of covering these topics in this manner, and while at first I was unsure if they really warranted their own book, I did not realize how poorly I understood the semantics of "this." I would highly recommend the text to anybody who expects to do much work in Javascript, in particular in creating or working with frameworks, where a full knowledge of the topics covered could prove indispensible. After reading this text, I would be interested in reading the other texts in the series as well.

              (I received an electronic copy of the book as part of OReilly's reader review program.)

              (0 of 1 customers found this review helpful)

               
              5.0

              Essential reading

              By Tom Dan

              from Ca

              About Me Developer

              Verified Buyer

              Pros

              • Accurate
              • Concise
              • Helpful examples
              • Well-written

              Cons

                Best Uses

                • Expert
                • Intermediate

                Comments about oreilly You Don't Know JS: this & Object Prototypes:

                Great book, highly recommended.

                (3 of 3 customers found this review helpful)

                 
                5.0

                great explanation

                By Lewis

                from Berkeley, CA

                About Me Developer

                Verified Buyer

                Pros

                • Concise
                • Helpful examples

                Cons

                • Combative Tone

                Best Uses

                • Intermediate

                Comments about oreilly You Don't Know JS: this & Object Prototypes:

                I was pretty ignorant of inheritance and how 'this' works. This book got me up to speed, and now I'm using call, apply, etc in my code. The book has this idea called OLOO that I've found pretty useful, too.

                Displaying reviews 1-10

                Back to top

                Previous | Next »

                 
                Buy 2 Get 1 Free Free Shipping Guarantee
                Buying Options
                Immediate Access - Go Digital what's this?
                Ebook:  $18.99
                Formats:  DAISY, ePub, Mobi, PDF
                Print & Ebook:  $24.19
                Print:  $21.99