添加javascript中类似json对象的数量

Question

我希望结果是同一只猫的所有数量之和。

var  data = [
{ cat: 'EK-1',name:"test",info:"mat", quantity: 3},
{ cat: 'EK-2', name:"test2",info:"nat"quantity: 1}
];

我尝试这样做下面我有一个数组的对象有一些类似的对象。如何添加数量和创建独特的对象。下面我已经给出了我所尝试的。

var data = [{
cat: 'EK-1',
name: "test",
info: "mat",
quantity: 1
},
{
cat: 'EK-1',
name: "test",
info: "mat",
quantity: 1
},
{
cat: 'EK-1',
name: "test",
info: "mat",
quantity: 1
},
{
cat: 'EK-2',
name: "test2",
info: "nat",
quantity: 1
}
];
const products = Array.from(data.reduce((acc, {
cat,
quantity
}) =>
acc.set(cat, (acc.get(cat) || 0) + quantity),
new Map()
), ([cat, quantity]) => ({
cat,
quantity
}));
console.log(products);

Answer 1

您可以使用Array#reduce，使用累加器传递新对象:

var data = [ { cat: "EK-1", name: "test", info: "mat", quantity: 1, }, { cat: "EK-1", name: "test", info: "mat", quantity: 1, }, { cat: "EK-1", name: "test", info: "mat", quantity: 1, }, { cat: "EK-2", name: "test2", info: "nat", quantity: 1, }, ];
let seen = [];
const res = data.reduce((acc, { cat, ...rest }) => {
const idx = seen.indexOf(cat);
if (idx == -1) (acc.push({cat, ...rest}), seen.push(cat));
else acc[idx].quantity++;
return acc;
}, []);
console.log(res);