Question 259186 in Javascript Question posted in
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Javascript – Checking if an item is inside a nested object

I have the following nested object:

const sites = [
 {
  "name": "name1",
  "list": [
     {
       "id":1,
       "name": "Year",
       "type": "int"
     }
  ]
 }
]

I would like to check if one item is present in the object by checking the id:

const item1 = {
       "id":1,
       "name": "Year",
       "type": "int"
     }
const item2 = {
       "id":2,
       "name": "Month",
       "type": "int"
     }

So I do:

sites.some(i => i.list.some(j => j.id === item1.id)) //True

sites.some(i => i.list.some(j => j.id === item2.id)) //False

Is there a better way to do this query without using so many .some?

Tags:

2

Answers


  1. 0

    Your .some approach is perfectly reasonable. Use functions to keep DRY.

    function isItemPresent(sites, item) {
  return sites.some(site => site.list.some(subItem => subItem.id === item.id));
}

const item1 = {
  "id": 1,
  "name": "Year",
  "type": "int"
};

const item2 = {
  "id": 2,
  "name": "Month",
  "type": "int"
};

console.log(isItemPresent(sites, item1)); // true
console.log(isItemPresent(sites, item2)); // false

    If you want to use Lodash, it can make it a little more negligibly short.

    function isItemPresent(sites, item) {
  return _.some(sites, site => _.some(site.list, { id: item.id }));
}
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  2. 0

    2 some()‘s are the fastest way for 2 checks. So it’s totally ok.
    If you have many items in the lists and check many items I would suggest gather IDs in a Set, then the checking is trivial:

    const set = new Set(sites.flatMap(i => i.list.map(j => j.id)));

console.log(set.has(item1.id));
console.log(set.has(item2.id));
    <script>

const item1 = {
       "id":1,
       "name": "Year",
       "type": "int"
     }
const item2 = {
       "id":2,
       "name": "Month",
       "type": "int"
     }
const sites = [
 {
  "name": "name1",
  "list": [
     {
       "id":1,
       "name": "Year",
       "type": "int"
     }
  ]
 }
];
     
</script>
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