Rest parameters

ES6 introduces rest parameters. Rest parameters allow us to send an arbitrary number of parameters to a function in the form of an array. Rest parameter can only be the last one in the list of parameters, and there can only be one rest parameter. Putting a rest operator(...) before the last formal parameter indicates that parameter is a rest parameter. The following example shows adding a rest operator before the last formal parameter:

    function sayThings(tone, ...quotes){ 
      console.log(Array.isArray(quotes)); //true 
      console.log(`In ${tone} voice, I say ${quotes}`) 
    } 
    sayThings("Morgan Freeman","Something serious"," 
     Imploding Universe"," Amen"); 
    //In Morgan Freeman voice, I say Something serious,
     Imploding Universe,Amen 

The first parameter passed to the function is received in tone, while the rest of the parameters are received as an array. Variable arguments (var-args) have been part of several...