I try many ways to solve this. I can remove duplicate values. but the problem is updating total_product value. How can I do this? Give me some hints.
const colors = [
{ "name": "Black", "total_product": 1 },
{ "name": "Black", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
]
const colors = [
{ "name": "Black", "total_product": 2 },
{ "name": "White", "total_product": 4 }
]
You can use new Map() or simple object to store the count of same objects:
const colors = [
{ "name": "Black", "total_product": 1 },
{ "name": "Black", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
];
const colorsMap = new Map();
colors.forEach(color => {
if (colorsMap.has(color.name)) {
colorsMap.set(color.name, colorsMap.get(color.name) + 1);
return;
}
colorsMap.set(color.name, 1);
});
const groupedColors = [];
colorsMap.forEach((value, key) => {
groupedColors.push({
name: key,
total_product: value
});
})
console.log(groupedColors);It's a good case for reduce which "boils down" an array to an accumulator value. Here, reduce (doc) can be used to create objects that count occurrences of each name...
const colors = [
{ "name": "Black", "total_product": 1 },
{ "name": "Black", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 },
{ "name": "White", "total_product": 1 }
];
const counts = colors.reduce((acc, obj) => {
if (!acc[obj.name]) acc[obj.name] = { name: obj.name, total_product: 0 };
acc[obj.name].total_product++;
return acc;
}, {});
const result = Object.values(counts);
console.log(result);The intermediate value counts produced by reduce looks like this...
{
"Black": {
"name": "Black",
"total_product": 2 // <- incremented each time we found a "Black"
},
"White": {
"name": "White",
"total_product": 4 // <- incremented each time we found a "White"
}
}
Object.values(), like the name implies, makes an array of the values.
It makes no sense to return an Array since you already squashed the array to unique names and their respective values, simply reduce to Object:
const colors = [
{name:"Black", total_product:1},
{name:"Black", total_product:1},
{name:"White", total_product:1},
{name:"White", total_product:1},
{name:"White", total_product:1},
{name:"White", total_product:1},
];
const sumColors = colors.reduce((ob, item) => {
ob[item.name] ??= 0
ob[item.name] += item.total_product;
return ob;
}, {});
console.log(sumColors); // {"Black": 2, "White": 4}