Microsoft Delivers Version 2.0 of TypeScript Programming Language

Microsoft announced the final release of its TypeScript 2.0 programming language, a superset of JavaScript, available as a download with Visual Studio Code.

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Microsoft on Sept. 22 announced the formal release of TypeScript 2.0, which is available as a download as well as with Visual Studio Code. TypeScript 2.0 is Microsoft's programming language that is a superset of JavaScript.

Microsoft launched TypeScript in 2012 and released TypeScript 1.0 two years ago. With TypeScript, Microsoft does JavaScript one better with a programming language that enables JavaScript developers to build enterprise-scale applications.

The TypeScript project was led by Anders Hejlsberg, the father of Microsoft's C# language.Hejlsberg spoke with eWEEK about the 1.0 release.

"JavaScript is tremendously popular these days and is sort of the only game in town when it comes to cross-platform, but it also is a dynamically typed language that was never really intended for more than 100- or maybe 1,000-line apps," he said. "And now people are regularly writing 100,000- or 1 million-line apps in JavaScript. And those apps become tremendously hard to write and even harder to maintain once they get beyond a certain size—about tens of thousands of lines or so. It's hard because JavaScript lacks a lot of these large-scale application-structuring concepts like classes and modules and interfaces, and also static typing is notably absent in JavaScript."

Yet since 1.0, TypeScript has grown not only as a language but also as a community, Microsoft said. In its launch of the Angular 2 JavaScript development framework, Google relied on partner Microsoft for key tools and expertise.

TypeScript 2.0 brings several new features that enhance developer productivity, advances TypeScript's alignment with ECMAScript's evolution, provides wide support for JavaScript libraries and tools, and augments the language service that powers a first-class editing experience across tools, Microsoft's TypeScript team said in a blog post.

Indeed, TypeScript 2.0 delivers several new features over even the 1.8 release, Microsoft said. New features include simplified declaration file acquisition, non-nullable types, control flow analyzed types and the read-only modifier. Other new features include tagged unions, the new never type, "this" types for functions and glob support in tsconfig.

Microsoft said that last month alone, TypeScript had more than 2 million downloads compared with just 275,000 in the same month last year.

"In addition, we've had tremendous adoption of the TypeScript nightly builds with over 2,000 users participating in discussion on GitHub and 1,500 users logging issues. We've also accepted PRs from over 150 users, ranging from bug fixes to prototypes and major features," the TypeScript team blog said.

Moreover, DefinitelyTyped, the repository for high-quality TypeScript type definitions, is another example of the TypeScript community growing and maturing.

"Starting out as a small repository of declaration files, it now contains over 2,000 libraries that have been written by hand by over 2,500 individual contributors," the TypeScript team blog said. "It is currently the largest formal description of JavaScript libraries that we know of. By building up DefinitelyTyped, the TypeScript community has not only supported the usage of TypeScript with existing JavaScript libraries but also better defined our understanding of all JavaScript code."