Dexter  Goodwin

Dexter Goodwin

1628364300

Find out JavaScript private class fields & TypeScript private modifier

In this post we'll shed light on ECMAScript private fields and see how they compare to the TypeScript private modifier.

JavaScript private class fields and the need for privacy

A closure is the only JavaScript native mechanism for protecting variables from access.

Closures are the foundation for a lot of private-like patterns, like the popular module pattern. But after ECMAScript 2015 classes took over in recent years, developers felt the need for more control over classes member privacy.

#typescript 

What is GEEK

Buddha Community

Find out JavaScript private class fields & TypeScript private modifier

Private Class Fields and Methods in JavaScript Classes

JavaScript private class fields and methods are new features for JavaScript classes. In this tutorial, you will learn all you need to know about this feature. You will learn about what private methods and class fields are and how they work. You will also learn how to use them in your projects.

Introduction

When you want to add some data to JavaScript class you can do so through class properties. These properties are by default always public. This also means that they are publicly accessible and modifiable. The same also applies to class methods. They are also public by default.

This might often be okay. However, sometimes, you may want to keep some properties or methods private. You may want to make them inaccessible from the outside of the class they are defined in. This is where private methods and class fields can be handy.

Keeping it private

The idea of keeping some things private is simple and straightforward. When you want to keep something private, be it a property or method, it should be accessible only from one place. This place is the class in which you defined that property or method.

If you try to access private class field or method from elsewhere JavaScript should not allow it. This includes outside the class in which the class field or method is defined. Also any instance of that class. However, it is possible to access private class field from a method inside the same class.

#javascript #javascript classes #javascript private class

JavaScript Private Class Fields and The TypeScript Private Modifier

In this post we’ll shed light on ECMAScript private fields and see how they compare to the TypeScript private modifier.

JavaScript private class fields and the need for privacy

closure is the only JavaScript native mechanism for protecting variables from access.

Closures are the foundation for a lot of private-like patterns, like the popular module pattern. But after ECMAScript 2015 classes took over in recent years, developers felt the need for more control over classes member privacy.

The class field proposal (at the time of writing in stage 3) tries to solve the problem with the introduction of private class fields.

Let’s see how they look like.

#typescript #javascript

Dexter  Goodwin

Dexter Goodwin

1628364300

Find out JavaScript private class fields & TypeScript private modifier

In this post we'll shed light on ECMAScript private fields and see how they compare to the TypeScript private modifier.

JavaScript private class fields and the need for privacy

A closure is the only JavaScript native mechanism for protecting variables from access.

Closures are the foundation for a lot of private-like patterns, like the popular module pattern. But after ECMAScript 2015 classes took over in recent years, developers felt the need for more control over classes member privacy.

#typescript 

Coy  Roberts

Coy Roberts

1600481520

Javascript array find: How to Find Element in Javascript

Javascript array find() is an inbuilt js function that returns the value of the first item in the Array that satisfies a provided testing function. Otherwise,  undefined will be returned. The array find() method returns the value of the first element in an array that passes a test of provided function.

If an Array find() method finds an item where the function returns a true value. Javascript find() returns the value of that array item immediately and does not check the remaining values of that Array.

Javascript array find

Javascript Array.find() is the inbuilt function that is used to get a value of the first item in the Array that meets the provided condition. If you need an index of the found item in the Array, use the  findIndex(). If you need to find an index of the value, use Array  .prototype.indexOf(). If you need to find if the value exists in an array, use Array  .prototype.includes().

It checks all the items of the Array, and whichever the first item meets, the condition is going to print. If more than one item meets the condition, then the first item satisfying the requirement is returned. Suppose that you want to find the first odd number in the Array. The argument function checks whether an argument passed to it is an odd number or not.

Javascript find() function calls an argument function for every item of the Array.  The first odd number for which argument function returns true is reported by the find() function as the answer.

#javascript #javascript find #array.find

Hans  Marvin

Hans Marvin

1636269900

TypeScript option you want to enable beyond strict : noUncheckedIndexedAccess

strict (and its sub flag strictNullChecks) can really help prevent null and undefined errors in your runtime #JavaScript. However, it doesn't defend against invalid array and object access.

In this lesson we look at a flag that protects against rogue undefined that might end up in your #TypeScript if this flag is not enabled 

#typescript #javascript