What is `cdk` in Angular Material 2 components

CDK (Component Development Kit) is a standalone package.

The goal of the CDK is to give developers more tools to build awesome components for the web. This will be especially useful for projects that want to take advantage of the features of Angular Material without adopting the Material Design visual language.

Checkout the repo from Google for CDK

https://github.com/angular/material2/tree/master/src/cdk

CDK is the short form of component dev kit. This signifies that these are general-purpose tools for building components that are not coupled to Material Design

From the material2 changelog

• Several components in core/, such as Overlay, have had their prefix changed to cdk- (short for "component dev kit"). This signifies that these are general-purpose tools for building components that are not coupled to Material Design.The old selectors are still available as deprecated but will be removed in the next release. The CSS classes have been changed.

For more info on how to use cdk components such as table, overlay, portal, portal host, e.t.c, you can find examples here:

1. https://github.com/angular/material2/tree/master/src/demo-app
2. https://medium.com/@caroso1222/a-first-look-into-the-angular-cdk-67e68807ed9b