TypeScript 1.4 Available Now

TypeScript 1.4 is available now with more new features.
TypeScript 1.4 comes with many improvements that can summarized below: 
  • Union Types: Allows you to specify that a value is one of a number of various types using a union type. Union types are a new kind of type and work any wher you can specify a type.

  • Type Guards: A common pattern in JavaScript is to use typeof or instanceof to examine the type of an expression at runtime. TypeScript now understands these conditions and will change type inference accordingly when used in an if block.

  • Type Aliases: With this release you can now define an alias for a type using the type keyword

  • Const Enums: In TypeScript 1.4, you’ll be able to make const enums.
Along with those improvements the release has some improvements in the new ES6 output mode, support for let and const, and support for ES6 template strings. The goal is to make TypeScript 2.0 release fully support the ECMAScript 6 standard.
Try the new features with Visual Studio 2015 CTP5, Visual Studio 2013, NPM, and as source.
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