It is used only when tsc is run with no specified input files. The file tsconfig.json contains configuration options for the TypeScript compiler. To see the version of TypeScript that is installed, enter npx tsc -v. Add the following npm script in package.json:.ts files, place them in and under the src directory. Create a src directory at the top of your project directory.Modify tsconfig.json to match the starting point described in the next section.Tsc is an abbreviation for 'TypeScript Compiler.' node_modules/.bin for executables installed by npm. The file created will contain many commented-out options. Locally install the TypeScript compiler (and optionally the type definitions for Node) by running npm install -D typescript Create a tsconfig.json file by running npx tsc -init.Create a package.json file by running npm init.Create a directory for the project and cd to it.Let's get started by creating a TypeScript project. For example, TypeScript allows adding a number and a string (resulting in concatenation), but it does not allow adding an object and a number.

TypeScript addresses most of these issues by disallowing many type coercions that JavaScript allows. For a humorous summary of some of these, see Gary Bernhardt's 'WAT' talk. One of the criticisms of JavaScript is that many seemingly invalid expressions actually produce a result, rather than triggering an error at runtime.

Disallows many JavaScript type coercions.

Allows editors to flag errors while typing and provides completion.Otherwise some errors described here will not be reported. The example code here assumes that the most strict TypeScript settings possible are in effect. This article assumes knowledge of JavaScript and focuses on the features that TypeScript adds.Įxperience with a language that has classes and interfaces like C# or Java is helpful. The TypeScript compiler requires Node.js to be installed in order to run. TypeScript source files have a file extension of. Specifying more types allows TypeScript to find more errors. TypeScript is an open source programming language developed and maintained by Microsoft ( ). At the end, it lists features that most developers should avoid. This article presents the most valuable parts of the TypeScript language. But it also adds many features, some of which are beautiful and some not so much. Therefore, it contains the same beautiful features and blunders that are present in JavaScript. TypeScript is a superset of the JavaScript language. The combination of features added to JavaScript in ES2015 (ES6) and beyond, plus the use of ESLint, makes JavaScript quite a nice language. In his book, JavaScript: The Good Parts, Douglas Crockford states, 'In JavaScript, there is a beautiful, elegant, highly expressive language that is buried under a steaming pile of good intentions and blunders.'

Js the good parts