JSFiddle - React, Tailwind, and code Playground

by Ed Griebel

HTML

<h1>out:</h1>
<div id='out' class='out'></div>
<hr/>

JavaScript

objects = [
    { env: 'prod', alias: 'foo'}, 
    { env: 'prod', alias: 'bar'}, 
    { env: 'dev',  alias: 'baz'}
];
keyfield = 'env';
var keys = $.unique($.map(objects, function (e) {
    return e[keyfield];
}));
var out = $.map(keys, function (e) {
    var ret = {};
    ret[e] = $.grep(objects, function (gr) {
        return gr[keyfield] == e;
    }).length;
    return ret;
});
$('#out').append('<li> Keys: ' + keys);
$('#out').append('<li> Summation: ' + $.map(out, function(el) { return JSON.stringify(el); }) );