UseReducer with TypeScript

UseReducer with TypeScript


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UseReducer with TypeScript
Cayla  Erdman

Cayla Erdman


What’s New In Typescript 4.0?

Today I am going to talk about new features in Typescript 4.0.

TypeScript 4.0 comes with lots of new features to make JavaScript development easier.

Labeled Tuple Elements

You can label tuple elements.

You can write:

type Range = [start: number, end: number];

to restrict args to have a string and a number.

you can also write:

type Foo = [first: number, second?: string, any[]];

to have rest entries in your tuple.

If your tuple has type Foo, then the tuple starts with a number and a string.

Then the rest of the entries can be anything.

Labels don’t require you to name your variables differently when destructuring.

For example, if you have:

function foo(x: [first: string, second: number]) {
  const [a, b] = x;

then you can name the destructured variables anything you want.

#software-development #typescript-with-react #typescript #typescript-4 #react native

Christa  Stehr

Christa Stehr


Microsoft Releases TypeScript 4.0 With Speed Boosting Features

icrosoft recently announced the availability of TypeScript version 4.0. The developers at the tech giant claimed that this version of the language represents the next generation of TypeScript with more expressivity, productivity as well as scalability.

Developed by the tech giant, TypeScript is an open-source programming language that is built on top of JavaScript by adding syntax for static type definitions. The types in this language provide a way to describe the shape of an object, providing better documentation as well as allowing TypeScript to validate that the code is working correctly.

According to the latest Stack Overflow Developers survey 2020, it secured the second position as the most loved language and  9th position among 25 programming languages as the most commonly used programming language by the developers. In one of our articles, we discussed how TypeScript weighs over other programming languages.

It is one of the fastest-growing programming languages among the developers. The motive behind this language is that while writing down the types of values and where they are used, developers can use TypeScript to type-check the code and let them know about mistakes before they run the code. TypeScript compiler can be used to strip away types from the code, leaving them with clean, readable JavaScript that runs anywhere.

In the present scenario, TypeScript is a core part of many developer’s JavaScript stack. The language adds optional types to JavaScript that support tools for large-scale JavaScript applications for any browser, for any host and on any operating systems.

The program manager of TypeScript, Daniel Rosenwasser, said in a blog post, “In our past two major versions, we looked back at some highlights that shined over the years. For TypeScript 4.0, we’re going to keep up that tradition.”

What’s New?

Based on the feedback by the developer’s community, TypeScript 4.0 includes many intuitive features that are focussed on boosting the performance of this language. Some of them are mentioned below-

Speed Improvements in build mode with –noEmitOnError

According to Rosenwasser, previously, compiling a program after a previous compile with errors under incremental would result in extremely slow performance when using the –noEmitOnError flag. The reason is, none of the information from the last compilation would be cached in a .tsbuildinfo file based on the –noEmitOnError flag.

But now TypeScript 4.0 changes this. The new update provides a great speed boost in these scenarios, and in turn, improves the build mode scenarios, which imply both –incremental and –noEmitOnError.

#developers corner #microsoft #microsoft releases typescript 4.0 #programming language #programming language with high salary #typescript #typescript 4.0

Yoshiko  Jones

Yoshiko Jones


What is TypeScript? Why TypeScript? and Why Not TypeScript?

Maybe you’ve been using JavaScript for a while and you’ve been hearing the buzz around… TypeScript. In this 2 part series, we’ll take a look at Why TypeScript? and Why Not TypeScript?

What is TypeScript?

According to the TypeScript website “TypeScript extends JavaScript by adding Types… TypeScript code is transformed into JavaScript code via the TypeScript compiler or Babel. This JavaScript is clean, simple code which runs anywhere JavaScript runs…”. In short, many refer to TypeScript as a superset of JavaScript.

In my opinion, this is kind of true and kind of not. Technically, not all valid JavaScript code can also be TypeScript code. We’ll talk about that later on. But, at its core, TypeScript was designed to allow developers to turn JavaScript, a dynamic programming language (one that is interpreted at runtime) into a statically typed programming language (one that is compiled before running). Let’s dive in.

Reasons For TypeScript

Improved Code Quality (potentially)

TypeScript makes use of features similar to languages like C## or Java: it truly is object oriented. This allows for more robust code. It enables the developer to implement type checking and make use of interfaces, classes, inheritance, etc. This can up the game as far as clean code when looking at a JavaScript program and a TypeScript program.

_Why did you throw in the word _potentially? Well, most valid JavaScript code can become TypeScript code. This means you don’t have to use the object oriented or typed features of TypeScript. Remember, TypeScript is optionally typed. It is not required. If TypeScript is utilized merely like JavaScript then improved code quality may not actually be a thing.

#typescript #programming #javascript #web-development #developer

Lawrence  Lesch

Lawrence Lesch


TypeScript Vs JavaScript: Which one Is Better?

Despite their similarities (which are a lot), whether JavaScript (JS) is really better than TypeScript (TS) - or vice-versa - lies in their differences.

This article seeks to explain the current main contrasts between both languages and provides code examples of each. Further, we will explain whether JS and TS are object-oriented programming (OOP) languages and which one a developer should learn.

Finally, we will disclose which is better! As we know, JavaScript is a language that has highly contributed to the web’s success. Is it time for TypeScript to take over? Let’s find out.

Table of Contents

What is JavaScript?

What is TypeScript

Difference between TypeScript and JavaScript

➤  Definition

➤  Compilation

➤  Typing

➤  Is JavaScript an object-oriented programming (OOP) language?

➤  Is TypeScript an object-oriented programming (OOP) language?

TypeScript vs JavaScript: code examples

Is TypeScript better than JavaScript?

TypeScript vs JavaScript: which one to learn?


What is JavaScript?

JavaScript (JS) is the most popular programming language in the world. It is considered a high-level language that helps to create interactive and dynamic web pages. Together with HTML and  CSS, JavaScript is also one of the core technologies for web applications and is highly characterized by its dynamic typing and just-in-time (JIT) compiler.

Plus, it is a multi-paradigm language due to its ability to support functional programming, imperative programming styles, and event-driven programming. JavaScript followed a client-side implementation (when the script runs on the user’s browser). However, it also has engines that allow server-side implementations (scripts run on the web server, and the response is customized according to each user’s request).

#development #typescript #typescript

Makenzie  Pagac

Makenzie Pagac


Your Reference Guide to Using TypeScript in React

One of the issues with JavaScript is its dynamically-typed nature, meaning that data and variable types are unknown until runtime. This can have many side effects. For example, it can cause confusion within your codebase due to the fact that a variable can be anything.

To solve this issue, Microsoft released TypeScript. Anders Hejlsberg, lead architect of TypeScript, said, “What if we could strengthen JavaScript with the things that are missing for large scale application development, like static typing, classes [and] modules…? That’s what TypeScript is about.”

TypeScript instantly became the most widely used static-typed version of JavaScript. It enabled JavaScript devs to statically type data and variables. Soon enough, it was introduced to React.js, enabling React devs to write their React app in TypeScript.

But this comes at a cost: TypeScript typings and syntaxes can be difficult to keep up with, especially when used with React.

React has many features, such as props, class components, function components, function params, components lifecycle hooks, and member properties. Because typing these within TypeScript isn’t easy, this article aims to serve as a quick reference and learning guide for both beginner and advanced React devs.

With it, you’ll be able to quickly look up best practices and generic TS types in React. Ready? Let’s get started.

TypeScript typings

TypeScript has a typings folder where it saves files with *.d.ts extension. These files include interfaces that infer what shape a value will take. This is what enables TypeScript to bring data-typing to JavaScript.

An interface describes what a value would look like:

type AppState {
    propOne: number;
    propTwo: string

AppState describes what the value of its data-type would look like. First, we infer it would be an object that holds properties propOne and propTwo, the former being of number type and the latter being a string type. Assigning a boolean type to propOne would cause TypeScript to throw TypeError.

When we include TypeScript in our React project, every React element has an interface that defines the shape it will take. Let’s start with function component.

Function component

Function components are normal functions that return JSX elements in React and are used to create views. Initially, they are stateless components, but with the arrival of React hooks, they can be made stateful and smart/

Defining a React function component takes the React.FunctionComponent shape:

function App: React.FunctionComponent<> {
    return (
            // ...

We can also use the shorthand React.FC:

function App: React.FC<> {
    return (
            // ...

React.FunctionComponent, or React.FC, describes explicitly the return type of the function component.

We can type the props definitions in the arrows <>.

type AppProps = {
    message: string;
    age: number;

AppProps is the interface the props passed to App will take, so we can write the App component below if it would receive props:

type AppProps {
    message: string;
    age: number;

function App: React.FC<AppProps>(props: AppProps) {
    return (
            // ...

We can use ? to set optional values in the typing:

type AppProps {
    message: string;
    age?: number;

Now, the age property becomes optional. The App component can be rendered, omitting the age property in its props object.

We can omit the type declaration within the arrows <>.

function App<{message: string; age: number;}>({message: string; age: number;}: AppProps) {
    // ...

Inner functions in the functional component can be typed, like so:

function App<{message: string; age: number;}>({message: string; age: number;}: AppProps) {
    // ...

    function clickHandler (val: number) {
        // ...

    return (
            <button onClick={() => clickHandler(45)}            

#typescript #typescript #javascript #web-development #developer