JSFiddle - React, Tailwind, and code Playground

HTML

data_1: <span id="data_1"></span> <br/>
data_2: <span id="data_2"></span>

JavaScript

var data_1;
var data_2;

fillValue(data_1,"First");
fillValue(data_2,"Second");

function fillValue(link2GlobalVar, value){
    window[link2GlobalVar] = value;
}   

console.log(data_1);
console.log(data_2);