Remove objects from nested array using Lodash

Question

I have the following JSON structure:

{
  "id": 123,
  "shops": [
    {
      "shopId": 456,
      "products": [
        {
          "productId": 10001,
          "name": "abc",
          "state": "active"
        },
        {
          "productId": 10002,
          "name": "def",
          "state": "expired"
        }
      ]
    },
    {
      "shopId": 789,
      "products": [
        {
          "productId": 20001,
          "name": "qrt",
          "state": "expired"
        },
        {
          "productId": 20002,
          "name": "jbf",
          "state": "active"
        }
      ]
    }
  ]
}

I want to remove all products from each shop where the product does not have certain properties.

If I covert it to a flat map then I can do it fine, but then I lose the outer object as I just have an array with all the products that haven't been removed in.

_(shopJson.shops).map('products').flatten().map(x => {if(x.state === 'active'){return x}}).compact().value()

I tried the following but just end up with an empty array:

_(shopJson.shops).map('products').filter(x => x.state === 'active').value()

I also tried using _.reduce() and _.transform() but can't get it to work

The final JSON should look like:

{
  "id": 123,
  "shops": [
    {
      "shopId": 456,
      "products": [
        {
          "productId": 10001,
          "name": "abc",
          "state": "active"
        }
      ]
    },
    {
      "shopId": 789,
      "products": [
        {
          "productId": 20002,
          "name": "jbf",
          "state": "active"
        }
      ]
    }
  ]
}

Alberto Trindade Tavares · Accepted Answer · 2020-02-23 22:23:26Z

3

You don't really need lodash for this. You can just use Array.prototype.map and Array.protype.filter (and also some spread syntax to shallow merge object properties):

const data = {id:123,shops:[{shopId:456,products:[{productId:10001,name:"abc",state:"active"},{productId:10002,name:"def",state:"expired"}]},{shopId:789,products:[{productId:20001,name:"qrt",state:"expired"},{productId:20002,name:"jbf",state:"active"}]}]};

const result = {
  ...data,
  shops: data.shops.map((shop) => ({
    ...shop,
    products: shop.products.filter((product) => product.state === 'active'),
  })),
};

console.log(result);

EDIT: As @Deykun pointed out, if you want to ignore shops that don't have any active products, you can filter shops out using Array.prototype.some in a filter:

const data = {id:123,shops:[{shopId:456,products:[{productId:10001,name:"abc",state:"active"},{productId:10002,name:"def",state:"expired"}]},{shopId:789,products:[{productId:20001,name:"qrt",state:"expired"},{productId:20002,name:"jbf",state:"expired"}]}]};
    
const result = {
  ...data,
  shops: data.shops
    .filter((shop) => shop.products.some((product) => product.state === 'active'))
    .map((shop) => ({
      ...shop,
      products: shop.products.filter((product) => product.state === 'active')
  }))
};

console.log(result);

edited Feb 23, 2020 at 22:23

answered Feb 23, 2020 at 22:03

Alberto Trindade Tavares

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2 Comments

Deykun Over a year ago

I agree that lodash is not needed here, but I would consider adding shops: data.shops.filter( s => s.products.some(p => p.state === 'active') ).map( ... to ignore shops without active products.

Alberto Trindade Tavares Over a year ago

@Deykun Good point. Edited my answer to mention this. Thanks! :)

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