DpackGetData/testarr.js

var arr = ['a', 'b', 'c', 'd', 'e', 'f','g','h','i','a','b','c','d','r','f','c','e','y','r'];
var result = [];
var idx = 0;

console.log(arr.slice(0,3))

for (var i = 0 ; i< arr.length; i += 3){
	if(i == 0){
		result[idx] = arr.slice(0,3);		
	}
	else if (i + 3 > arr.length){
		result[idx] = arr.slice(i)
	}
	else{
		result[idx] = arr.slice(i,i+3)
	}
	idx += 1;
	

}


// var indexToSplit = arr.indexOf('c');
// var first = arr.slice(0, indexToSplit);
// var second = arr.slice(indexToSplit + 1);

console.log(result);