Microsoft pursues JavaScript developers with TypeScript 1.8

Tech giant Microsoft has made TypeScript 1.8 available and is hoping to attract developers to migrate their JavaScript projects.

In version 1.8, .js JavaScript files now can output to .tsc, accessing the TypeScript compiler and allowing developers to convert JavaScript to TypeScript. “The TypeScript compiler checks the input .js files for syntax errors, and emits valid output based on the –target and –module flags,” the release notes state. “The output can be combined with other .ts (TypeScript) files as well.”

The upgrade also features a module augmentation capability that lets developers design more modular libraries.

Bowden Kelly, program manager for Visual Studio and .Net at Microsoft, in a blog said “This allows library authors to distribute their libraries in a piecemeal fashion. Previously, TypeScript made the assumption that modules wouldn’t change. With module augmentation, users have the ability to extend existing modules such that consumers can specify if they want to import the whole module or just a subset.”

Strings in a type position become string literal types in version 1.8. “Only exact string matches are assignable to string literal types, and like any other type, they can be used in union types as well. So if we rewrite the AnimationOptions interface with string literal types, the API users now get type protection,” Kelly added.

Version 1.8 features control flow analysis to help catch common programming errors. And statements not guaranteed to execute at runtime are now flagged as unreachable code errors; unused labels are flagged as well. Stateless function components from the React JavaScript UI library now are supported in TypeScript.

With TypeScript, Microsoft is providing a typed superset of JavaScript that compiles to JavaScript, similar to Google’s Dart or CoffeeScript