JSFiddle - React, Tailwind, and code Playground

by csornmo

HTML

<b>// Result should be</b>
<br><br>

customer: "company1", place: "place1", done: 1 <br>
customer: "company2", place: "place1", done: 2 <br>
customer: "company2", place: "place2", done: 1

JavaScript

var baseData = [
    {
        "date"  : "2020-02-23",
        "week" : "8",
        "vanlig" : 1,
		"glutenfri": 2
    },
    {
        "date"  : "2020-02-24",
        "week" : "9",
        "vanlig" : 2,
		"glutenfri": 4
    },
    {
        "date"  : "2020-02-24",
        "week" : "9",
        "vanlig" : 1,
		"glutenfri": 2
    }, 
    {
        "date"  : "2020-02-24",
        "week" : "9",
        "vanlig" : 1,
		"glutenfri": 2
    }
];

var newData = [];
baseData.forEach(function(item, index) {
	newData[item.date + item.week] = newData[item.date + item.week] ||
	{ date: item.date, week: item.week, vanlig: 0, glutenfri: 0 };
	
  	newData[item.date + item.week].vanlig += item.vanlig;
	newData[item.date + item.week].glutenfri += item.glutenfri;
});

console.log(Object.values(newData));