The TypeScript team recently announced version 3.1 of TypeScript, adding mappable tuple and array types and several other refinements.

Next TypeScript release, due February 25, will support a limited form of checking against conditional and indexed acces types in return statements.

When classes are more structure than you need, tuples let you specify simple type-safe aggregates of other data types. They'll also let you create a dictionary collection…but it won't be type-safe. In ...