JSFiddle - React, Tailwind, and code Playground

JavaScript

var Hello_0 = "Hello 0 !";
    
    console.log(" Hello_0 is: " + eval("Hello_"+0));
    
    var dinamyc_var = "Hello_"+1;
    
    if (eval(dinamyc_var) === undefined) {
         console.log(" dinamyc_var is undefined ");
    } 
    if (eval(dinamyc_var) === null) {
         console.log(" dinamyc_var is null ");
    }
    if ( typeof eval(created_node) === undefined ) {
         console.log(" dinamyc_var is typeof undefined ");
    }
    if ( typeof eval(created_node) === null ) {
         console.log(" dinamyc_var is typeof null ");
    }

    console.log(" dinamyc_var is: " + eval(dinamyc_var));