将 JSON 对象与键值组合

Question

I have multiple JavaScribt Objects that I bring to following format with JSON.stringify :

{"date":"2016-01-07T12:45:00.000Z",
 "duration":120,
 "location":"ExampleLocation"}

Now I would like to save these Objects into one Variable with the following format:

var labs = {
        "2016-01-07":[{
            "date":"2016-01-07T12:45:00.000Z",
            "duration":120,
            "location":"ExampleLocation"
        }],
        "2017-01-05":[{
            "date": "2017-01-05T14:45:00.000Z",
            "duration": 120,
            "location": "ExampleLocation"
        }], //etc
}

So I want to combine the Objects and draw one of the values as "key" to each object. I have absolutely no idea how to achieve this.

Answer 1

You should loop through objects array, create index from date property, then you should check if your grouped array contains this index, if yes, you should push current element to array under that index, if not you should create new array under that index and push current element to it.

Take a look on snippet below.

 var elements = [{"date":"2016-01-07T12:45:00.000Z", "duration":120, "location":"ExampleLocation1"}, {"date":"2016-01-04T12:45:00.000Z", "duration":120, "location":"ExampleLocation2"}, {"date":"2016-01-05T12:45:00.000Z", "duration":120, "location":"ExampleLocation3"}, {"date":"2016-01-07T12:45:00.000Z", "duration":120, "location":"ExampleLocation4"}, {"date":"2016-01-05T12:45:00.000Z", "duration":120, "location":"ExampleLocation5"}]; var groupedElements = {}; elements.forEach(function(element) { var index = element.date.slice(0, 10); if(groupedElements[index] === undefined) { groupedElements[index] = []; } groupedElements[index].push(element); }); document.write(JSON.stringify(groupedElements));

Answer 2

You can use reduce to create a new object grouping by date and putting the values in an array inside:

 var arr = [ {"date":"2016-01-06T12:15:00.000Z", "duration":120, "location":"ExampleLocation"}, {"date":"2016-01-06T12:45:00.000Z", "duration":120, "location":"ExampleLocation"}, {"date":"2017-07-07T12:45:30.000Z", "duration":120, "location":"ExampleLocation"}, {"date":"2017-07-07T12:45:44.000Z", "duration":120, "location":"ExampleLocation"}, ]; var grouped = arr.reduce((a, next) => { let key = next.date.split('T')[0]; a[key] = (a[key] || []).concat(next); return a; }, {}); console.log(grouped);