JSFiddle - React, Tailwind, and code Playground

HTML

<div class ="numeric"></div>

SCSS

.numeric {
  &.one {
    color; #FF0040;
  }
  
  &.two {
    color; #FFA243;    
  }
  
  &.three {
    color; #63ff00;    
  }
}

JavaScript

const nrClass = {
	'3': 'three',
  '2': 'two',
  '1': 'one'
}

const blah = number=>{
	const elem = document.getElementsByClassName("numeric")[0];
	elem.innerHTML = number;
  console.log(nrClass[number])
  elem.classList.add(nrClass[number]);
}

//blah(1);
//blah(2);
blah(3);