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ViewsHow to group nested array of objects in js
I have a nested array of objects. I'm trying to group product objects that have the same value.
Each objects has a vendor property containing an email. I am trying to group the objects by matching vendor email
This is how my database looks like:
[
{
_id: "622d70a49bd88b1599026318",
products: [
{
_id: "6223186e2278d4e502f5264a",
title: "Product number 1",
price: 600,
cartQuantity: 1,
vendor: {email: "vendor1@gmail.com"}
},
{
_id: "622d4e9f9bd88b1599026317",
title: "asdas",
price: 100,
cartQuantity: 5,
vendor: {
email: "vendor2@gmail.com"
}
},
{
_id: "622d4e9f9bd88b1599026317",
title: "asdas",
price: 100,
cartQuantity: 5,
vendor: {
email: "vendor2@gmail.com"
}
}
]
}]
I am trying to do it with the reduce method but the problem is with using map inside the reduce. It repeats the object many times. I am also unable to get the grouped objects.
const groupedMap = db.reduce(
(entryMap, e) => e.products.map((product) => entryMap.set(product.vendor.email, [...entryMap.get(product)||[], product])),
new Map()
);
The above code output is:
My expectation is:
[0: {"vendor1@gmail.com" => Array(1)}
key: "vendor1@gmail.com"
value: [{_id: '6223186e2278d4e502f5264a', title: 'Product number 1', price: 600, cartQuantity: 1, vendor: {email: "vendor1@gmail.com"}}],
1: {"vendor2@gmail.com" => Array(2)}
key: "vendor2@gmail.com"
value: [{_id: '6223186e2278d4e502f5264a', title: 'Product number 1', price: 600, cartQuantity: 1, vendor: {email: "vendor2@gmail.com"}},
{_id: '6223186e2278d4e502f5264a', title: 'Product number 1', price: 600, cartQuantity: 1, vendor: {email:"vendor2@gmail.com"}}
]
]
2 answers
Answer question0
Loop through each item in the array and see if the vendor email exists as a key already in a dictionary, if it exists push it to that array, otherwise set the value of the vendor email key equal to an array with the current item in it
See code below
const data = [{
_id: "622d70a49bd88b1599026318",
products: [{
_id: "6223186e2278d4e502f5264a",
title: "Product number 1",
price: 600,
cartQuantity: 1,
vendor: {
email: "vendor1@gmail.com"
}
},
{
_id: "622d4e9f9bd88b1599026317",
title: "asdas",
price: 100,
cartQuantity: 5,
vendor: {
email: "vendor2@gmail.com"
}
},
{
_id: "622d4e9f9bd88b1599026317",
title: "asdas",
price: 100,
cartQuantity: 5,
vendor: {
email: "vendor2@gmail.com"
}
}
]
}];
const mapped = {};
data[0].products.forEach(item => {
if (item.vendor.email in mapped) return mapped[item.vendor.email].push(item);
mapped[item.vendor.email] = [item];
});
const expectedFormat = Object.keys(mapped).map(key => {
const o = {};
o[key] = mapped[key];
return o;
});
console.log(expectedFormat)0
try to make an object where key is the value you group by. the next step is foreach in which you check each object in the array, whether the value you are looking for is in the object made - if not, then you filter the array by searched value and add the result to your object