In the array below, I want to group by item and reason, then calculate the total quantity:
item_movements = [
{
item: "Apple",
reason: 1,
quantity: 5
},
{
item: "Banana",
reason: 2,
quantity: 10
},
{
item: "Apple",
reason: 1,
quantity: 5
},
{
item: "Banana",
reason: 1,
quantity: 8
},
{
item: "Apple",
reason: 2,
quantity: 3
},
{
item: "Banana",
reason: 1,
quantity: 8
}
];
The result I am trying to achieve is this:
item_totals = [
{
item: "Apple",
1: 10,
2: 3
},
{
item: "Banana",
1: 16,
2: 10
}
];
I was able to group by item using Loadash like so:
({
itemMovementbyItem() {
var result = _(this.item_movements)
.groupBy(x => x.item)
.map((value, key) => ({
item: key,
item_movements: value
}))
.value()
return result
}
})
But I am having problems to group a second time by reason.
You could sum the properies directly after grouping by 'item'.
function itemMovementbyItem(array) {
return _(array)
.groupBy('item')
.map(group => ({
item: group[0].item,
1: _.sumBy(group, o => o.reason === 1 ? o.quantity : 0),
2: _.sumBy(group, o => o.reason === 2 ? o.quantity : 0)
}))
.value();
}
var item_movements = [{ item: "Apple", reason: 1, quantity: 5 }, { item: "Banana", reason: 2, quantity: 10 }, { item: "Apple", reason: 1, quantity: 5 }, { item: "Banana", reason: 1, quantity: 8 }, { item: "Apple", reason: 2, quantity: 3 }, { item: "Banana", reason: 1, quantity: 8 }];
console.log(itemMovementbyItem(item_movements));.as-console-wrapper { max-height: 100% !important; top: 0; }<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>Collected from the Internet
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