Take away:
- Always check you ruturn the accumulator
- Always pass in the inital value
var data = ["vote1", "vote2", "vote1", "vote2"];
var reducer = function(acc, value){
if(acc[value]){
acc[value] = acc[value] + 1;
}else{
acc[value] = 1;
}
return acc;
};
var res = data.reduce(reducer ,{});
console.log(res);