Joel Kelly

Joel Kelly

1565062140

An Overview of ES6 Classes

JavaScript introduced the class keyword in 2015 with the release of ES6. React made classes an indispensable language feature when they introduced support for using extends React.Component instead of React.createClass() in 2015, and removed support for React.createClass() entirely in 2017 in favor of classes. Today, classes are a fundamental part of JavaScript, and many new JavaScript devs don’t remember a time before classes. In this article, I’ll provide an overview of how classes work in JavaScript: how to declare classes, what features JavaScript provides with classes, and how inheritance works.

Working With Classes

Here’s how you define a basic class MyClass, and create an instance of MyClass.

class MyClass {
  constructor() {
    this.answer = 42;
  }
}

const obj = new MyClass();
obj.answer; // 42

You must instantiate a class with new. Calling MyClass() without new throws an error:

// TypeError: Class constructor MyClass cannot be invoked without 'new'
MyClass();

A class is technically a function, although the ECMAScript spec explicitly disallows calling a class without new. In fact, the typeof operator identifies MyClass as a function.

typeof MyClass; // 'function'
MyClass instanceof Function; //  true

To check whether an object is an instance of a class, you should use the instanceof operator. You can also check whether the constructor property is equal to MyClass.

obj instanceof MyClass; // true
// Works, but `instanceof` is better...
obj.constructor === MyClass;

// Because `instanceof` is immune to overwriting the `constructor` property
const obj = {};
obj.constructor = MyClass;
obj instanceof MyClass; // false
obj.constructor === MyClass; // true

Like functions, classes in JavaScript are variables like any other. You can assign a class to a variable, overwrite that class, and pass a class as a parameter to a function. Like functions, you can also declare classes with or without explicit names.

let Foo = class {
  constructor() {
    this.answer = 42;
  }
}

Foo = class {
  constructor() {
    this.answer = 43;
  }
}

console.log(Foo); // '[Function: Foo]'
console.log(new Foo()); // 'Foo { answer: 43 }'

Unlike functions, classes are never hoisted. In the below example the function Foo() prints successfully, because JavaScript looks ahead and ‘hoists’ Foo() to the top of the function. But trying to print the class Bar throws a reference error, because JavaScript does not hoist class definitions.

#es6 #javascript #web-development #programming #developer

What is GEEK

Buddha Community

An Overview of ES6 Classes

Yashi Tyagi

1617449307

CA Classes - Best CA Classes Online

Chartered Accountancy course requires mental focus & discipline, coaching for CA Foundation, CA Inter and CA Finals are omnipresent, and some of the best faculty’s classes have moved online, in this blog, we are going to give the best way to find online videos lectures, various online websites provide the CA lectures, Smartnstudy one of the best site to CA preparation, here all faculty’s video lecture available.

check here : ca classes

#ca classes online #ca classes in delhi #ca classes app #ca pendrive classes #ca google drive classes #best ca classes online

Duy  Tien

Duy Tien

1626358620

Sử dụng Class trong ES6 #8

Sử dụng Class trong ES6

#class #es6

Joseph  Murray

Joseph Murray

1624048020

How to Find All the Classes of a Package in Java

In this article let’s take a look at how to find all classes of a package in Java

To find all classes of a package in Java we can use the ClassHunter of Burningwave Core library. So we start by adding the following dependency to our pom.xml:

XML

1

<dependency>2
    <groupId>org.burningwave</groupId>3
    <artifactId>core</artifactId>4
    <version>8.4.0</version>5
</dependency>

The next steps are the following:

  • retrieving the ClassHunter through the ComponentContainer
  • defining a regular expression that we must pass to the **ClassCriteria **object that will be injected into the **SearchConfig **object
  • calling the **loadInCache **method that loads in the cache all loadable classes of the indicated paths, then applies the criteria filter and then returns the **SearchResult **object which contains the classes that match the criteria

#java #classes #class #packages #package #how to find all the classes of a package in java

Joel Kelly

Joel Kelly

1565062140

An Overview of ES6 Classes

JavaScript introduced the class keyword in 2015 with the release of ES6. React made classes an indispensable language feature when they introduced support for using extends React.Component instead of React.createClass() in 2015, and removed support for React.createClass() entirely in 2017 in favor of classes. Today, classes are a fundamental part of JavaScript, and many new JavaScript devs don’t remember a time before classes. In this article, I’ll provide an overview of how classes work in JavaScript: how to declare classes, what features JavaScript provides with classes, and how inheritance works.

Working With Classes

Here’s how you define a basic class MyClass, and create an instance of MyClass.

class MyClass {
  constructor() {
    this.answer = 42;
  }
}

const obj = new MyClass();
obj.answer; // 42

You must instantiate a class with new. Calling MyClass() without new throws an error:

// TypeError: Class constructor MyClass cannot be invoked without 'new'
MyClass();

A class is technically a function, although the ECMAScript spec explicitly disallows calling a class without new. In fact, the typeof operator identifies MyClass as a function.

typeof MyClass; // 'function'
MyClass instanceof Function; //  true

To check whether an object is an instance of a class, you should use the instanceof operator. You can also check whether the constructor property is equal to MyClass.

obj instanceof MyClass; // true
// Works, but `instanceof` is better...
obj.constructor === MyClass;

// Because `instanceof` is immune to overwriting the `constructor` property
const obj = {};
obj.constructor = MyClass;
obj instanceof MyClass; // false
obj.constructor === MyClass; // true

Like functions, classes in JavaScript are variables like any other. You can assign a class to a variable, overwrite that class, and pass a class as a parameter to a function. Like functions, you can also declare classes with or without explicit names.

let Foo = class {
  constructor() {
    this.answer = 42;
  }
}

Foo = class {
  constructor() {
    this.answer = 43;
  }
}

console.log(Foo); // '[Function: Foo]'
console.log(new Foo()); // 'Foo { answer: 43 }'

Unlike functions, classes are never hoisted. In the below example the function Foo() prints successfully, because JavaScript looks ahead and ‘hoists’ Foo() to the top of the function. But trying to print the class Bar throws a reference error, because JavaScript does not hoist class definitions.

#es6 #javascript #web-development #programming #developer

Target Class Does Not Exist In Laravel 8

As you all know laravel 8 already released and you can see there are many changes and update in laravel 8 version. many laravel users are facing issue in their new Laravel 8 version when they try to load their routes in web.php and they run into an Exception that says something like “Target class postController does not exist”.

Target Class Does Not Exist In Laravel 8

https://websolutionstuff.com/post/target-class-does-not-exist-in-laravel-8

#target class does not exist in laravel 8 #error #target class controller does not exist #target class not found #laravel #target class does not exist error solved