How to make reactive variables between COMPONENTS? Angular 2/4 : Good Stackers, Today I propose a doubt that I can not find or identify.

Lately I'm practicing with the **Inputs / Outputs** and this has led me to do this example:

In component A, I have `@Output () outputVariableA = [hi, hi2, hi3]`

In component B, I have  `@Input () inputVariableB [];`

In component B, I define a function that modifies the inputVariableB.

How do I make it REACTIVE, between the two VARIABLES the modification 
And that the modified data of the **inputVariableB** is reflected in the **outputVariableA**

> If it has not been understood, ask me.

Thank you very much for helping!