问题
The following answer to this question does a great job explaining the differences between classical inheritance and prototypal inheritance. this was of interest to me to understand because I started working in Java, but moved over to Javascript.
In his answer, he states for prototypal inheritance that, "All of the business about classes goes away. If you want an object, you just write an object."
Yet there is so much documentation and questions on how to "write classes" in Javascript.
Why is there push to make the language something it is not. I'm looking for concrete examples of cases where using classes in JS applications are more sensible in this prototypal language and the benefits of awkwardly fitting a square peg into a round hole. As Aravind put it, why are people learning Javascript by comparing it to others, and not as it was intended... and why is this practice seemingly encouraged?
Bottomline question: Why are classes being introduced in ECMAScript 6?
回答1:
The masses like classes.
There's nothing "more" or "less" natural about prototypal inheritance, this is entirely subjective. JS is its own language, just like Smalltalk and Self had different ideas about what it meant to be an object.
ES6 classes are syntactic sugar. They normalize/clean up how inheritance/etc are to be used in JS.
Similar to CoffeeScript, they attempt to standardize how OOP is done in JS, and make it more familiar to people that aren't used to prototypal inheritance.
回答2:
Why are people learning Javascript by comparing it to others, and not as it was intended?
This gets into cognitive and learning theory, but the short version is that humans like things that are familiar, and one of the ways we learn is by relating new ideas to knowledge we already have.
Why are classes being introduced in ECMAScript 6?
Classes were almost introduced in ECMAScript 4, actually. I think there are good arguments for OOP being a useful pattern for writing complex software, and class based inheritance is more familiar to many programmers than is prototype based inheritance. I think an equally valid question might be "why does JavaScript still implement prototype based inheritance when most people who learn it will be more comfortable with class based inheritance?"
If you're curious what classes in JavaSCript might look like, take a look at ActionScript 3, which is based on that draft of EMCAScript 4 with class based inheritance.
Of course, just because ECMAScript adds class support does not mean that JavaScript will, or at least that it will any time soon.
回答3:
I found this article by Zakas explaining it clearly, that it's just syntactic sugar, and at the end of the day Javascript will work the same way.
Don't worry about having to learn classes or having to shift your programming styles, nothing changes. :)
回答4:
Why are classes being introduced in ES6? Sugar, of the syntactic variety.
回答5:
Classes are very good for people who come to JavaScript from object-oriented languages (like Java).
This is the experience I've made several times already. I had a number of J2EE web projects with good Java dev teams, who had some JavaScript knowledge, but not much. Almost the first thing I did was to explain prototypes, prototypal inheritance and how one can implement the OOP paradigm using prototypes - basically the pseudoclassical inheritance. (Now I routinely do a "JavaScript for Java Developers" workshop almost in every project of that kind.)
With that approach I mostly saw good code coming out. Most Java developers tend to stick to the pseudoclassical pattern and are quite happy with it. This is most probably not what JS ninjas out there would write, but, frankly, I don't care. The code is easy to understand and to maintain, people had a good learning curve and were productive very fast.
回答6:
Prototype languages, like JavaScript, are really great for small scale, short term projects that don't require a lot of testing or maintenance. Their simple and flexible functionality really shines in this realm.
Class based languages on the other hand tend to be a little more rigid and require more setup, which isn't as great at the little stuff but the extra structure is helpful to keep the larger, long term projects scalable and manageable.
When JavaScript first started, its primary function was to manipulate static DOM elements, which is a great application for a prototype language. Fast, flexible and simple -- no fuss. Now, however, the role that JavaScript fills is much more complex and is more and more an application than a simple script. Adding classes to a prototype language does sound a little funny, but the added structure classes provide, along with their widespread familiarity could very easily help teams of developers handle the complexity of modern JavaScript applications.
来源：https://stackoverflow.com/questions/27069519/class-use-in-a-prototypal-inheritance-based-language