es6_spread_array.js

var alphabet = ["a","d","e","h","i"],
    firstSet = ["b","c"],
    secondSet = ["f","g"];

//Without Spread operator

Array.prototype.splice.apply(alphabet,[1,0].concat(firstSet)); //[a,b,c,d,e,h,i]
Array.prototype.splice.apply(alphabet,[4,0].concat(secondSet)); //[a,b,c,d,e,f,g,h,i]

console.log("Without Spread Operator: ",alphabet); //[a,b,c,d,e,f,g,h,i]

//Using Spread operator

var alphabetWithSpread = ["a",...firstSet,"d","e",...secondSet,"h","i"];

console.log("With Spread Operator: ",alphabetWithSpread); //[a,b,c,d,e,f,g,h,i]