如何根据数组的值将数组对象转换/过滤为新的json对象？

Question

I have one object array like this:

[{id: 1, name: 'foo', sport: 'soccer'},
{id: 2, name: 'bar', sport: 'basketball'},
{id: 3, name: 'acme', sport: 'basketball'},
{id: 4, name: 'xyz', sport: 'baseball'}]

How can I transform this array of objects into an new javascript object that is filtered by the sport value ? Something like this:

{
    soccer: [{id: 1, name: 'foo'}],
    basketball: [{id: 2, name: 'bar'},{id: 3, name: 'acme'}],
    baseball: [{id: 4, name: 'xyz'}]
}

Answer 1

Try this:

var test = [{id: 1, name: 'foo', sport: 'soccer'},
{id: 2, name: 'bar', sport: 'basketball'},
{id: 3, name: 'acme', sport: 'basketball'},
{id: 4, name: 'xyz', sport: 'baseball'}];

test.reduce(function(aggregator, item) {

    if(!aggregator[item.sport]) {
        aggregator[item.sport] = [];
    }

    aggregator[item.sport].push({id: item.id, name: item.name})

    return aggregator;

}, {});

Answer 2

You could use Array.prototype.reduce() https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce

Something like this:

array.reduce(function (accumulator, currentValue) {
  var sport = currentValue.sport;
  delete currentValue.sport;
  accumulator[sport] = accumulator[sport] || [];
  accumulator[sport].push(currentValue)
  return accumulator;
}, {});