how to change theme angular2 sass

I will allow a user to choose a theme, basically a set of SASS color variables with the new colors. How would be the best way of going about changing this when the user selects from a drop down in sass file i have 5 theme files how to implement in angular 2
Its possible?

```
@import 'mixins';
@import 'colorSchemes/material';
// @import 'colorSchemes/darktheme';
// @import 'colorSchemes/redtheme';
// @import 'colorSchemes/bluetheme';
// @import 'colorSchemes/Greentheme';
@import 'variables';