TypeScript 5.0 New Features

Let's look at the major features added in TypeScript 5.0.

1. Decorators

Standard decorators are finally introduced.

function logged(target: any, context: ClassMethodDecoratorContext) {
  return function (...args: any[]) {
    console.log('Method called')
    return target.apply(this, args)
  }
}

class Example {
  @logged
  greet() {
    return 'Hello!'
  }
}

2. const Type Parameters

More accurate type inference is now possible.

3. Performance Improvements

Build speed improved by 10-25%.