Count number of items in an array of objects with a specific property value (JavaScript)

I have an array of objects. Note that "created" sometimes has the same value more than once. Also note that "status" is sometimes "0":

var array = [ {"created":"Jan 1","status":1}, {"created":"Jan 1","status":1}, {"created":"Jan 2","status":1}, {"created":"Jan 3","status":0}, {"created":"Jan 4","status":1}, {"created":"Jan 4","status":1} ];

I want a new a new array of objects like this:

var newArrayA = [ {"Jan 1":2}, {"Jan 2":1}, {"Jan 3":0}, {"Jan 4":2} ];

OR a multidimensional array like this (I'm not sure which is better for D3.js):

var newArrayB = [ ["Jan 1",2], ["Jan 2",1], ["Jan 3",0], ["Jan 4",2] ];

So, when "status" is "1", it counts the number of "created" that are the same. And when status is "0", that is also included.

How do I do this? Here's what I have so far JSFIDDLE. Is this how to approach it? Or am I missing some simple solution? Thanks!


D3 would cope with either result format - it does slightly depend on what you want to do with it. Regardless, here is some example code for generating either format:

var result = {};
array.forEach(function(i) {
if (!result.hasOwnProperty(i.created)) {
result[i.created] = 0;
if (i.status === 1) {
result[i.created] += 1;

var newArrayA = Object.keys(result)
.map(function(k) {
var o={};
o[k] = result[k];
return o;

var newArrayB = Object.keys(result)
.map(function(k) { return [k,result[k]] })

Category:javascript Time:2018-12-01 Views:1

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