How to use loader on variable in js?

Question

webpack

Hello, I have a line

let str = "/*some scss code that should be compiled to css*/";

and I need to get css line from it using sass-loader.
In the case of require, I could turn the scss file into a css line,

require('!sass-loader?{"sassOptions":{"indentWidth": "0"}}!..myScssFile.scss')

But what about a variable instead of a file?