prototypal | JS inheritance done right | Transpiler library
kandi X-RAY | prototypal Summary
kandi X-RAY | prototypal Summary
All utilities in this namespace should work with every JavaScript engine, down to IE6, Opera Mini, duktape, nodejs, and all others.
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Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of prototypal
prototypal Key Features
prototypal Examples and Code Snippets
Lines of Code : 33
License : No License
Copyconst { format } = require('winston');
const volume = format((info, opts) => {
if (opts.yell) {
info.message = info.message.toUpperCase();
} else if (opts.whisper) {
info.message = info.message.toLowerCase();
}
return info;
});
Community Discussions
Trending Discussions on prototypal
QUESTION
class Human{
talk(){
return 'talking';
}
}
class SuperHuman extends Human{
constructor(){
super();
this.age = 12;
}
fly(){
return 'flying';
}
}
let me = new Human();
let you = new SuperHuman();
you.gender = 'male';
console.log(you);
let she = Object.create(you);
console.log(she);
ANSWER
Answered 2021-May-09 at 10:11Devtools is just telling you that the prototype of she is a SuperHuman (specifically, you), not that the prototype is the function SuperHuman.
The prototype chain of she is:
QUESTION
I have the following json file.
...ANSWER
Answered 2021-May-08 at 06:46Well once you parsed the data now you have your object in memory and you can operate with it as you wish. You can extract the lines you tell about in the following way
QUESTION
I am learning NodeJS and learning prototypal inheritance.
Below is the code I am using for prototypal inheritance .
The issue I am facing is :
The meow, purr and hiss methods do get called on leopardObj.
But , whenever I call below methods , inside those methods , this.name is always coming as undefined.
ANSWER
Answered 2021-Apr-15 at 11:57meow, purr and hiss functions are arrow functions, so you have bind your context incorrectly. Change them to regular functions back and everything will work as expected:
QUESTION
This is what I don't understand, and reading about it is over my head. I need a very dumbed down version to ever understand it:
Creating prototypal inheritance: Previously, you have created generic custom object for task that had a number of attributes (task name, description etc). Now, you will demonstrate your knowledge of prototypal inheritance by creating a top level task object and different types of tasks based on category. For example, you may have a task category of Grocery that will have different attributes than a task category of Education. However, both types of tasks will need to inherit some generic attributes and methods from the parent task object.
I also don't really understand how to store tasks as objects or why you would need to do this in the context of a task list, and how you would do it. I think this would be the first step before prototypal inheritance? Thank you to anyone who has the time to explain.
I'm currently failing my JavaScript Advanced class, so any tips are appreciated!
...ANSWER
Answered 2021-Mar-22 at 06:36$(document).ready(function () {
var task = {
name: "",
description: "",
status: "",
eta: "",
priority: "",
owner: "",
initiate() {
console.log("Starting Task");
this.status = "IN PROGRESS";
console.log(this);
},
complete() {
console.log("Ending Task");
this.status = "COMPLETED";
console.log(this);
}
};
var education = {
grade: "",
studentName: "",
subjects: [],
__proto__: task
};
var grocery = {
items: [],
budget: "",
spend: "",
__proto__: task
};
education.grade = "10th";
education.studentName = "Diana";
education.subjects = ["Science", "History"];
education.name = "Complete Assignments";
education.description = "Useful for better grades";
education.initiate();
education.complete();
});
QUESTION
I am trying to understand the difference between Prototypal Inheritance and Classical Inheritance in Javascript. I came across some articles claiming The abstraction level for prototypal inheritance is never deeper than 1, but I don't understand why. Is that because the last inherited prototype has access to methods or properties of all its ancestors, whereas classical inheritance only has access to its last ancestor?
An example of accessing methods from all ancestors:
Simple graph to show inheritance:
...ANSWER
Answered 2021-Mar-09 at 03:36It's a complicated way of saying: "In JavaScript, everything is a concrete object that exists in the JS engine, not an abstraction."
This is important! It means that Generalizations (like the overarching Shoe concept) are just other Objects. With Classical Inheritance, Generalizations are abstractions of abstractions of abstractions... all the way down to the most recent descendant.
The abstraction level here is never deeper than 1; The only abstraction that occurs with Prototypal Inheritance is the abstraction away from real-world things.
So, in his way of putting things, the only abstraction is:
QUESTION
I am learning prototypal inheritance in Javascript, and I want to create prototype method that would use closures to same some data instead of accepting all of them as parameters.
Using map() of Array.prototype.map() as an example:
ANSWER
Answered 2021-Mar-03 at 03:26You're assigning a value to the map property of the instance in your MyArray constructor. Every time the constructor runs to construct a new instance, a newly created function gets assigned to the map property.
Just remove the this.map assignment inside the constructor entirely.
QUESTION
So i'm trying to setup prototypal inheritance using the surrogate method and I have run into a behavior that seems weird for me. Here are my classes:
...ANSWER
Answered 2021-Jan-06 at 17:42using the surrogate method
Protip: Use Object.create for this which has been standard for a decade now :-)
It becomes an instance of Animal?
No. It's still exactly the same object and no functionality changed. It's an instanceof Animal just like it had been before.
The Animal {} you see in the console is a custom display choice of the debugger.
Why is this happening?
My guess would be that you see a side effect of an internal optimisation that occurs when an object is assigned as the .prototype of a function, which is observable in the debugger only.
QUESTION
I am learning JS now, as I am new so was looking for inheritance in JS. I came accross 2 words:
- Prototypal Inheritance
- Prototype Chain
Can you please tell me if both are same or different? Please, I am new and am very confused. Pl help. thanks in advance.
...ANSWER
Answered 2020-Oct-02 at 12:24I think for all intents and purposes they are referring to the same concept for someone learning JS. Are they two distinct concepts requiring separate studying of both? No. They're just two terms that relate to the same concept of inheritance in JS.
A loose analogy which I know is not perfect, but should help make sense of the two terms and how they relate:
I have a father from whom I inherited my genetics. My father inherited his genetics from his father, and so on. This is my prototype chain.
You also have a father from whom you inherited your genetics. Your father inherited his genetics from his father, and so on. That is your prototype chain.
We are both using prototypal inheritance but we have different prototype chains.
Some developers like to argue semantics and get all technical just to flex on others, but if you are a beginner learning JS you absolutely do not need to stress that these two terms are referring to different areas of study because they are not.
QUESTION
I had never seen syntax like below, where a variable is directly initialized by appending to the class name (except in case of static members)
...ANSWER
Answered 2020-Sep-21 at 13:56Any property directly assigned to a class, like with Fruit.count = 0;, is considered to be a validly assigning static variable/member. One actually uses the constructor as namespace.
Examples ...
QUESTION
I've learned about the function constructors and function factories,
to implement inheritance when using function constructors, we use the prototype property:
...ANSWER
Answered 2020-Sep-08 at 14:02You can put getName method directly to the constructed object. Do not use prototype in the "non-prototype" creation.
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