Typescript Typings Example

Marius Schulz Front End Engineer. 0: Even Better Data Typing and Class Discriminants If you care about data typing and want to avoid null/undefined errors, there's a lot you're going to like in TypeScript 2. Also since TypeScript 1. Announcing TypeScript 2. Also, I've always felt the best way to learn is to do. Now we can create a sandbox directory, enter it and install the typings:. Without the ability to add 'Type Information' to an existing package, it would be difficult to validate the code of any object from a package. It was a mystery for me, how you can use it to write large applications. This middleware is only configured in development builds. I ran across this trying to find an example of using redux-thunk with typescript. For example if we want to install lodash we can run the following command to get the typings for it: npm install--save-dev @types/lodash. And your developer experience will skyrocket. for converting your controller actions to TS glue code for calling them etc. Successful build with many errors in typescript typing files. The source files are a mixture of JavaScript files (libraries provided by Adobe, e. Declaration files, if you’re not familiar, are just files that describe the shape of an existing JavaScript codebase to TypeScript. TypeScript and RequireJS (Keep It Simple) I'm not the first to take a look at mixing TypeScript and RequireJS but I wanted to get it clear in my head. Inferred Typing TypeScript also uses a technique called inferred typing, in case you do not explicitly specify the type of your variable. 2013-05-22 angular asp. If you're upgrading an app from a previous version of the API to the latest version you can run the following command in your TypeScript project. Announcing TypeScript 2. npm install --save restify # this will install restify into node_modules *and* add it to dependencies in your package. Typings is the simple way to manage and install TypeScript definitions. TypeScript's static typing will address the scalability problem. My thing uses MSBuild integration, so your typings is being regenerated each MVC (or any other) project build. This is all somewhat controversial and opinionated, but after accumulating experience in Java, Scala and JavaScript, many of us feel this way. TypeScript was developed under Anders Hejlsberg, who also led the creation of the language C#. He whipped out his phone and trotted down the stairs, typing a response to one of the many texts he'd received. Both of the code examples will result in the same JavaScript output but the declare example is more readable and expresses an ambient declaration. TypeScript is a compile-to-JavaScript language, which was released by Microsoft as an open source project in 2012. 3Today we're excited to bring you our latest release with TypeScript 2. The TypeScript handbook contains excellent general information about writing definitions, and also this example definition file which shows how to create a definition using ES6-style module syntax, while also specifying objects made available to the global scope. I want to declare a function with a error-first callback in a project using typscript with noImplicitAny and strictNullChecks. VS Code's TypeScript IntelliSense understands many standard JSDoc annotations, and uses them to show typing information and documentation in suggestions, hover info, and signature help. TypeScript also refers to the compiler, which transcompiles code written in the TypeScript syntax to JavaScript, which is widely supported across most browsers. For example consider the following scenario: Start a new Empty W…. A TypeScript function is like a. If you use these in a conditional block, TypeScript will understand the type of the variable to be different within that conditional block. It holds source code in "src", compiles js into "bin", and has a "package. Now we can create a sandbox directory, enter it and install the typings:. ts using reference path. ts extension. When the first big refactor comes around, you'll be a typescript convert for life. TypeScript have this sort of,. onclick = function (event: MouseEvent) {alert ('Clicked');};. let myVariable = 'Hello World'; In this example, we have not assigned any type to the variable. Gradual typing: TypeScript is an example of a gradual type system [14], where parts of a program are statically typed, and others dynamically typed through the use of a distinguished dynamic type, written any. Setting up a TypeScript web site in Visual Studio 2015 Update 1 is simple, but there are a few things to remember. In other words interfaces can be defined as reusable types for function. json file in your current directory/package, such as:. This means that our function above doesn't return anything. In your TS Definition file, e. TypeScript is an open-source object-oriented language maintained by Microsoft. In the same example:. Your First Class Component. According to TypeScript, Duck-Typing is a method/rule used to check the type compatibility for more complex variable types. Prerequisites: node. With TypeScript 1. use of TypeScript to create AngularJS controllers, communication with Web API services from TypeScript using AngularJS ajax functionality, use of strongly typed TypeScript declarations for AngularJS objects. As an app gets larger, with more actions and more complex reducers, it is all too easy to lose the structure of the root state and to pass inappropriate data through action payloads. Scan to open With an Android phone, you can scan this QR code with your Expo mobile app to load this project immediately. It can also be used when JavaScript applications are to be built on both client side and server side. This is a basic example of getting started with React Hooks in a TypeScript app but provides the environment and typings to experiment with Hooks. So TypeScript only cares about what types can do, not what they are called or where they exist in a type hierarchy. Typescript input onchange event. We are about to develop the famous TODO App from the TodoMVC project using React and TypeScript:. We will be. ts: instructs the TypeScript compiler to include the vscode API definition. This post should help you (and me) setup a typescript console app within a minute. TypeScript provides the duck typing type-checking which focus on the shape that values have. I had to create a quick console app in Typescript a few days back to test a few things. Using a TypeScript declaration file, for example, for procuring information and getting code prompts on functions,arrays, methods, etc is one of its uses. [15] check the correctness of TypeScript Interfaces for JavaScript libraries. When the first big refactor comes around, you'll be a typescript convert for life. TypeScript and RequireJS (Keep It Simple) I'm not the first to take a look at mixing TypeScript and RequireJS but I wanted to get it clear in my head. An Interface is a structure that acts as a contract in our application. Their system analyses the snapshot of the heap after library initialisation and performs a static analysis on the functions. That's why Vue ships with official type declarations for TypeScript - not only in Vue core, but also for vue-router and vuex as well. Static vs dynamic typing in typescript 4. It offers classes, modules, and interfaces to help you build robust components. There's no obvious difference between TS's project and Egg's in js: The suffix is ts in typescript style; typings folder is used to put d. It defines the syntax for classes to follow, which means a class that implements an interface is bound to implement all its members. By typing the properties, TypeScript will tell me if I typo a property or forget to pass one, which is really valuable. for Backbone. Define typescript. For more information see this blog post. TypeScript gives you a taste of future JavaScript, with typings. I want TypeScript 2. Here, the word typing refers to assigning types to program variables. To learn what TypeScript annotations should be used for each API, study the lifecycle API in the React docs and the corresponding typings. Despite that good quality typings are available, it is not straightforward how to get up to speed with Sequelize and TypeScript. It supports static typing and class based object oriented programming. Shortcut : ctrl+alt+l or cmd+alt+l. I had to create a quick console app in Typescript a few days back to test a few things. The definitive step-by-step guide to use DefinitelyTyped typings for applications written in TypeScript. Travis, for example, is a very compelling choice for CI when. A while back we talked about how TypeScript 2. json" EDIT added link to VSCode. json, tsconfig. TypeScript has the potential to bring the following benefits to a Redux application: Type safety for reducers, state and action creators; Easy refactoring of typed code; A superior developer experience in a team environment; A Practical Example. TypeScript also encourages dynamic typing of variables. We take the example from the website, and try to make it type safe. Implicit typing, on other hand, is performed by the compiler without us stating the variable type. Both TypeScript features which I describe briefly in this part of the article were introduced in TypeScript 3. During the midst of September, version 2. vue-typescript Typescript decorators to make vue play nice with typescript. TypeScript Using Travis CI with a Software Delivery Machine. Polyglot means a person that speaks multiple languages, where as for developers they're programming languages. To do so, we use an example project which you can access anytime later. js) execution. It is a strict syntactical superset of JavaScript, and adds optional static typing to the language. To learn what TypeScript annotations should be used for each API, study the lifecycle API in the React docs and the corresponding typings. But with time you’ll see that the more you add types, the more your code becomes robust. The global variable foo contains the number of widgets present. 0, and I’ve already covered them in my article about TypeScript 3. Every TypeScript example and tutorial I have found thus far is about language features, Static typing, Visual Studio, etc. Language Service is designed for text editing when low-latency feedback for the developer is crucial. Writing AngularJS 1. You have an apparently well-defined typings. Using TypeScript can help avoid painful bugs people commonly run into when writing JavaScript by type-checking your. TypeScript has the flag --noImplicitAny to prevent situations like the one in Case 2. And your developer experience will skyrocket. let myVariable = 'Hello World'; In this example, we have not assigned any type to the variable. I cannot find anything to tell me how I should be using it with reference to JavaScript and the DOM. How do we use this with TypeScript though so that our state is strongly-typed? Let's find out … I walked though an example of useState a few weeks ago where the state was defined as follows with useState hooks:. "typings/index. vue-typescript Typescript decorators to make vue play nice with typescript. ts `, you can add this line: declare module "*. When it comes to consuming existing JavaScript code in TypeScript, you have a few options at your disposal. In this case, you would want to define your own typings definition. ts using reference path. The TypeScript handbook contains excellent general information about writing definitions, and also this example definition file which shows how to create a definition using ES6-style module syntax, while also specifying objects made available to the global scope. Microsoft's TypeScript extends many familiar features of. TypeScript simply allows developers to opt in to the static typing approach whenever it will benefit them. If we do not have TypeScript compiler we install it with npm: npm install -g typescript. TypeScript in 2017 with JavaScript Framework Examples for example a type would be a number one like this. I would like to go through crucial elements and show how to maximize safety coming from static typing when using Sequelize. The tag was originally set up to refer to an old typings solution, as in the npm package. I’ve also prepared code examples to demonstrate differences between TypeScript and JavaScript. Today we are going to learn how to use TypeScript with Node. It is a strict syntactical superset of JavaScript, and adds optional static typing to the language. ts file will allow the compiler to link the require instruction in your user’s code to the typings defined in the TypeScript files of your library. Comments (6) | March 9th, 2014. The example tests here will focus on testing the SimpleTodoModel as we have already created examples in the intern-examples repo for this and many other popular ToDoMVC example applications. Making the Angular2 docs default to TypeScript examples even caused more rage for people that wanted to use Angular and were not prepared to deal with a new technology or simply do not understand the benefits of static typing. TypeScript looks more verbose and sometimes redundant compared to JavaScript. Abstract This post explains how to use TypeScript in your apps for SharePoint. Writing modular code is a good idea. With duck typing, Typescript compares signatures of classes and allows object of one type to be used with an instance of another if the object’s type signature is same as, or is a subset of, the initiating class’s signature. In your TS Definition file, e. But with time you’ll see that the more you add types, the more your code becomes robust. During the midst of September, version 2. I had to install node typings to resolve the missing http reference and mime typings to resolve mime missing reference. HashSets are containers that store unique elements in no particular order, and which allow for fast retrieval of individual elements based on their value. TypeScript Type Assertion. TypeScript compiler uses tsconfig. Modern JavaScript is valid TypeScript, meaning that one can use TypeScript without changing a single line of code. json, we have a paths array were we have specified "*" which is for the external libraries types, and also "typings" which will be for the typings that are made by us. I ran across this trying to find an example of using redux-thunk with typescript. Keep in mind that when using JSDoc for TypeScript code, you should not include type annotations. For the sake of this example, I'm going to create a simple hello-world-ish console app that prints our public IP. While these examples will compile, the resulting code will be almost useless to you in TypeScript. My intent is to share the journey, not to claim this is the "best" way to use TypeScript. In an HashSet, the value of an element is at the same time its key, that identifies it uniquely. During the years, I've of course came to terms with JavaScript, and a solid understanding is necessary, to understand the behavior of TypeScript, just like understanding assembly help. Below are the Benefits / Advantages of TypeScript: Static Typing - TypeScript introduces some datatypes to JavaScript variables like number, string, boolean, any, object type. Then in the reducer, we first copy the state and then update the properties directly which keeps the typing intact. TypeScript is an open-source object-oriented language maintained by Microsoft. My thing uses MSBuild integration, so your typings is being regenerated each MVC (or any other) project build. TypeScript's handling of this in arrow functions is in line with ES6 (Read: Arrow Functions). In other words, if we don't specify the data type for a variable then TypeScript compiler finds what type of data is assigning the first type and sets the data type of this variable. In this case, I am using a tool called typings to install the missing definitions. TypeScript provides the duck typing type-checking which focus on the shape that values have. com Route Service ng. TypeScript and RequireJS (Keep It Simple) I'm not the first to take a look at mixing TypeScript and RequireJS but I wanted to get it clear in my head. But it has the same strong typing problem that SignalR had when it came to TypeScript. init method to properly set up dependency tracking. The TypeScript compiler emits JavaScript. json" EDIT added link to VSCode. Also since TypeScript 1. Use the following commands to do so: npm install -g typescript npm install -g typings. Great thanks for Jim Crowley from Microsoft to make the text awesome. As an app gets larger, with more actions and more complex reducers, it is all too easy to lose the structure of the root state and to pass inappropriate data through action payloads. Most projects use Redux alongside React, so it’s worth taking a look at how TypeScript works with the Redux. json file, which is a configuration file, and then a command prompt window to install these definitions. Consensus: SignalR + TypeScript 03 July 2013 on Consensus. 你可以随意调用泛型参数,当你使用简单的泛型时,泛型常用 T、U、V 表示。 如果在你的参数里,不止拥有一个泛型,你应该使用一个更语义化名称,如 TKey 和 TValue (通常情况下,以 T 作为泛型的前缀,在其他语言如 C++ 里,也被称为模板). And in some respects it's ahead of C# (which should come as no surprise since TypeScript and C# were conceived by the same man). I know TypeScript well, but I am learning Vue and leaning on the experts from the Vue document and TypeScript team's resources on Vue for much of what I accomplished. 0 used in development). The are various benefits to using TypeScript, a few of these include: Thanks to static typing, TypeScript code is more predictable and easier to debug than JavaScript. Have you seen this before? If not, let's explain because the same principle applies when typing arrays. Check, here we are using the typings of file3. It supports static typing and class based object oriented programming. Conditional types are definitely an advanced feature of TypeScript's type system. value Angular 1. I would like to go through crucial elements and show how to maximize safety coming from static typing when using Sequelize. He whipped out his phone and trotted down the stairs, typing a response to one of the many texts he'd received. An example of using Omit can be seen in Ramda to describe the result of a function called omit (quite a surprise, huh?). Using 3rd Party TS Libraries via Typings PRO. I have a problem with some modules, for example `rx` and others, though some works. npm install typings --global # Install i. Even if I will encourage you to use all the power of types (in chapter 2), TypeScript do a fairly good work on ES-next feature set transpiling. Even if “TypeScript” contains “type”, the language do not force use to use types. TypeScript gives you a taste of future JavaScript, with typings. Packages can use type definitions from various sources and different versions, knowing they will never conflict for users. The are various benefits to using TypeScript, a few of these include: Thanks to static typing, TypeScript code is more predictable and easier to debug than JavaScript. For the sake of this example, I'm going to create a simple hello-world-ish console app that prints our public IP. TypeScript allows you to provide static type information for existing (untyped) code via external files, which have the file name extension. Component typings. At this point, neither the Angular 2 application nor the TypeScript compiler knows about this file; so, we have to install it as a custom Typings file. js file, you will need to indicate the main declaration file in your package. refinement typing to scripts have proven to be impractical due to the interaction of the machinery that accounts for im-perative updates and higher-order functions [5] (§6). So you can use it as a framework and its typings and. just what I wanted to say is, please try not introduce new technologies and thereby complexities without having a good reason to do so. I want to do a graphics thing and the browser is the natural target these days. TypeScript Type Assertion. In this article, you will learn implementing basic TypeScript examples on SharePoint, using Visual Studio. As an example of the type of tests I am talking about, have a look at the section “Writing Jasmine unit tests for our Backbone Collection” in my latest blog on Marionette : TypeScript: Using Backbone. The first thing you’ll probably notice is that data properties are defined directly on the class. json—TypeScript compiler configuration. Even if I will encourage you to use all the power of types (in chapter 2), TypeScript do a fairly good work on ES-next feature set transpiling. 3Today we're excited to bring you our latest release with TypeScript 2. TypeScript's static typing will address the scalability problem. ts `, you can add this line: declare module "*. A more comprehensive example, but we digress. I opened an issue on redux-thunk, but did not receive much help: reduxjs/redux-thunk#213 (comment). Any arbitrary object's instance 'o' can be declared with type 'I' if 'o' has same properties x and y; this feature is known as "Duck Typing". While we do not provide much examples yet, we highly appreciate any help to provide some useful examples. This normally autocompletes just typing "res". What sorts of search phrases do you think they will be typing in on Google? He sobered, staring at the screen a moment before typing again. So, there's no need to write your absolute first TypeScript file, because you already did without knowing so, but let's make a little "hello world!" by explicitly making a TypeScript file, and compile that to JavaScript. The are various benefits to using TypeScript, a few of these include: Thanks to static typing, TypeScript code is more predictable and easier to debug than JavaScript. This Type definition file tells the TypeScript compiler that there is a "module" type that has an "id" property (of type String). The JavaScript language has a handful of types, for example, String, Number, and Boolean, but TypeScript adds in few more primitive types to the list, such as Tuple, Enum, and Never. In your TS Definition file, e. JavaScript. useReducer. The first thing you’ll probably notice is that data properties are defined directly on the class. TypeScript uses the duck-typing method to compare one object with other objects by checking that both objects have the same type matching names or not. Including declarations in your npm package # If your package has a main. I’ve also prepared code examples to demonstrate differences between TypeScript and JavaScript. All the valid JavaScript code that you write is also valid TypeScript code. A simple example application using the React bindings. TypeScript 2. This post should help you (and me) setup a typescript console app within a minute. This page will walk through getting started with Angular 2 using TypeScript step by step example. Difference between TypeScript and JavaScript: TypesScript is known as Object oriented programming language whereas JavaScript is a scripting language. x is a front end JavaScript framework that has gained huge traction and popularity in the development community. Writing AngularJS 1. Also install the typings in order to exploit TypeScript’s strong type checking:. The more you help TypeScript to understand the intent of your code by adding type annotations, the more you’ll be fine later. Starting up the project. Tagged control framework, custom control, pcf, TypeScript Tip #863: Learn TypeScript This morning we released episode 50 of CRM Audio, and our guest Daryl Labar talked about TypeScript, an open source superset of JavaScript that adds optional typing, classes, syntax, and Intellisence. Duck typing in Typescript example program code : Duck-typing is a powerful feature which brings strong typing concepts in TypeScript code. React Apollo Hook options and result types are listed in the Hooks API section of the docs. The official TypeScript wiki on codeplex. Now this is something, isn't it? The core of Redux and similar state management libraries baked into a hook. GitHub Gist: instantly share code, notes, and snippets. TypeScript Using Travis CI with a Software Delivery Machine. TypeScript 2. And here’s a CodeSandBox with most of the above examples:. TypeScript brings lots of advantages to the JavaScript world with almost mandatory typings. An enhanced version of the above code is found under samples/typescript. TypeScript (TS) is the primary language for Angular going forward (2. As part of my 4 part series in creating the app I described in my prior post, I am going to be creating an online planning poker application for distributed teams using AngularJS, SignalR, and TypeScript. This is the only command that I manually run since using. Redux is a perfect candidate for Typescript. First of all we need some setting up. This has been depreciated since TypeScript version 2. We will be. The second command will install the typings for the JavaScript API from npm into a node_modules folder. Fastify is shipped with a typings file, but you may need to install @types/node, depending on the Node. package for typing is @types/lodash. 0 made it easier to grab declaration files for your favorite library. catch (if rejected). For example: npm install --save-dev @types/jquery. x is a front end JavaScript framework that has gained huge traction and popularity in the development community. Now we can create a sandbox directory, enter it and install the typings:. Here we explain how to use the for loops in TypeScript. You’ll also explore how TypeScript integrates with the Angular framework, which was built using TypeScript. Note: In many cases, the @types/react package provides type helpers like React. To set this up, start a new MVC project and let’s get Knockout and Jasmine installed into the project, along with their TypeScript definitions:. You should see the TypeScript. The –save flag tells npm to store the package information in our package. Keep in mind that when using JSDoc for TypeScript code, you should not include type annotations. Without looking up or pausing in her typing she issued directions. The TypeScript compiler can also load typings that are bundled with npm packages. So TypeScript only cares about what types can do, not what they are called or where they exist in a type hierarchy. Using createStyles to defeat type widening. I know TypeScript well, but I am learning Vue and leaning on the experts from the Vue document and TypeScript team's resources on Vue for much of what I accomplished. In this course, you’ll learn the latest TypeScript syntax constructs as well as the process of turning your TypeScript code into JavaScript. Of course the first section of this course also shows you how and where to get TypeScript, what tools you can use (there are several), and how to start writing code with it. Let's do this now. Having large frameworks, like Angular 2 and EmberJS embrace it have given it a lot of focus. Is there a way to declare a interface or type that allows two different signatures and works when calling?. I have typescript and typings installed globally npm install typescript typings -g but included them in the devDependencies section just in case some people don’t want to install those globally. Usage with TypeScript The AWS SDK for JavaScript bundles TypeScript definition files for use in TypeScript projects and to support tools that can read. In case you have been using TypeScript you may have used the tsd command line utility for installing TypeScript definition files from DefinitelyTyped. Inferred Typing in TypeScript. In other words interfaces can be defined as reusable types for function. Marionette and REST WebAPI (Part 2). There is also a utility called typings (npm install --save-dev typings) that can be used to manage third party typings from a variety of sources. I prefer to use Webpack because it gives. ts file will allow the compiler to link the require instruction in your user's code to the typings defined in the TypeScript files of your library. The second command will install the typings for the JavaScript API from npm into a node_modules folder. Typescript Tutorial Example | Beginners Guide To Typescript is today’s topic. Also since TypeScript 1. TypeScript's handling of this in arrow functions is in line with ES6 (Read: Arrow Functions). TypeScript and RequireJS (Keep It Simple) I'm not the first to take a look at mixing TypeScript and RequireJS but I wanted to get it clear in my head. This has been depreciated since TypeScript version 2. So, there's no need to write your absolute first TypeScript file, because you already did without knowing so, but let's make a little "hello world!" by explicitly making a TypeScript file, and compile that to JavaScript. ts file contains external module then you have to use import {Type} from "filepath" to use in other files. Typescript fundamentals 2. Using createStyles to defeat type widening. You can find a typed example of each Hook below. json My TypeScript project template is a good example of everything I just talked about. Typescript Tutorial Example | Beginners Guide To Typescript is today’s topic. Simple, right? Naturally, there's more to typing a function than just the snippet above can show. The definitive step-by-step guide to use DefinitelyTyped typings for applications written in TypeScript. TypeScript has the potential to bring the following benefits to a Redux application: Type safety for reducers, state and action creators; Easy refactoring of typed code; A superior developer experience in a team environment; A Practical Example. json file as well. TypeScript vs JavaScript: Learn The Difference If you're considering taking up web application development as a career, or even as a serious hobby, the question will arise, what language should you invest your time and efforts in. Typescript has been evolving quickly in the last few months, and one of the things that have evolved more is its most differentiating feature: the Typescript type definitions. Let’s look at some specific ES2015 and TypeScript features below, so you can make up your own mind whether to use ES2015 or TypeScript on your project. When the code containing these type annotations is compiled, everywhere the variable or parameter is references is checked to see if the usage conforms with the stated type. And your developer experience will skyrocket. October 12, 2015 Working with React and TypeScript. Even if I will encourage you to use all the power of types (in chapter 2), TypeScript do a fairly good work on ES-next feature set transpiling. A presentation created with Slides. getElementsByTagName ('div'); nodeList. VS Code's TypeScript IntelliSense understands many standard JSDoc annotations, and uses them to show typing information and documentation in suggestions, hover info, and signature help. Learn how to create your own type definition files and how to contribute to the TypeScript community at DefinitelyTyped # Helping your community is AWESOME # It is Saturday evening and it's raining a lot in Ireland. There is also a utility called typings (npm install --save-dev typings) that can be used to manage third party typings from a variety of sources. Simple, right? Naturally, there's more to typing a function than just the snippet above can show. TypeScript looks more verbose and sometimes redundant compared to JavaScript. I have typescript and typings installed globally npm install typescript typings -g but included them in the devDependencies section just in case some people don’t want to install those globally. Great example to get up and running with angular and typescript. json, we have a paths array were we have specified "*" which is for the external libraries types, and also "typings" which will be for the typings that are made by us. In other words, a JavaScript library may define a function: export function createPerson(name, age. With duck typing, Typescript compares signatures of classes and allows object of one type to be used with an instance of another if the object’s type signature is same as, or is a subset of, the initiating class’s signature. It defines the syntax for classes to follow, which means a class that implements an interface is bound to implement all its members. It's useful. ts extension. In the above example, empDept is marked with ?, so objects of IEmployee may or may not include this property. Setup the new application mkdir foo && cd foo npm init --yes foo. npm install -g typescript The -g means it’s installed on your system globally so that the TypeScript compiler can be used in any of your projects. If you have tried Flow and TypeScript, and you liked the typing experience but are looking for a different approach, I think Reason is at least worth 5 minutes. We have to compile them into something it can understand first. Most projects use Redux alongside React, so it's worth taking a look at how TypeScript works with the Redux. TypeScript is a free open-source programming language developed and maintained by Microsoft. 0 for non-nullable types (finally). NET world, is very easy to use, and meshes well with. If you're upgrading an app from a previous version of the API to the latest version you can run the following command in your TypeScript project.