Sum javascript object propertyA values with same object propertyB in array of objects

Question

How would one take a javascript array of objects such as:

my objArr = [
{key:Mon Sep 23 2013 00:00:00 GMT-0400, val:42},
{key:Mon Sep 24 2013 00:00:00 GMT-04         


        

Answer 1

you can also try using javascript linq framework which is exactly same as sql statement which is given desired output with less written code and effective and found at linq.js

var objArr = 
[
{key:'Mon Sep 23 2013 00:00:00 GMT-0400', val:42},
{key:'Mon Sep 24 2013 00:00:00 GMT-0400', val:78},
{key:'Mon Sep 25 2013 00:00:00 GMT-0400', val:23},
{key:'Mon Sep 23 2013 00:00:00 GMT-0400', val:54}
];


var aggregatedObject = Enumerable.From(objArr)
        .GroupBy("$.key", null,
                 function (key, g) {
                     return {
                       key: key,
                       contributions: g.Sum("$.val")
                     }
        })
        .ToArray();

console.log(aggregatedObject);

which is pretty easy as compare to looping. i hope this may help.