Summarize array of objects and calculate average value for each unique object name

Question

I have an array like so:

var array = [
     {
       name: \"a\",
       value: 1 
     },
     {
       name: \"a\",
       value: 2 
     },
     {
                


        

Answer 1

And a possible solution using ECMA5 (as we seem to be missing one)

var sums = {},
    averages = Object.keys(array.reduce(function (previous, element) {
        if (previous.hasOwnProperty(element.name)) {
            previous[element.name].value += element.value;
            previous[element.name].count += 1;
        } else {
            previous[element.name] = {
                value: element.value,
                count: 1
            };
        }

        return previous;
    }, sums)).map(function (name) {
        return {
            name: name,
            average: this[name].value / this[name].count
        };
    }, sums);

On jsFiddle