Filtering array of objects with arrays based on nested value to extract specific fields

Question

Something related to the same question as question..

var mainArray = [{ "name":"George", 
                  "nest": [{"id": 1, "age": 11},{"id": 2, "age": 22}]}, 
                { "name":"George", 
                  "nest": [{"id": 2, "age": 34}]}, 
                { "name":"Raghu", 
                  "nest": [{"id": 3, "age": 45}]}, 
                { "name":"Sudhir", 
                  "nest": [{"id": 4, "age": 23}]}];
var filteredGeorge = mainArray.filter(element => element.name === "George")
var final = filteredGeorge.map(element => ({"name": element.name, "id": element.nest.filter(element => element.age == 22)}))
console.log(final)

What I am interested in output is actually something like:

  {
    "name": "George",
    "id": 2      
    ]
  }

It need not even be an array, else it can even be just an array of this object.

I am mainly looking for the name and id value or say there was one more key called say dept after name, then dept and id is what I want finally where name is George and age is 22.

What if there are multiple items with same name? – Karan Singh Jun 24 '20 at 21:31 — Karan Singh, Jun 24 '20 at 21:31

Benjamin Eckardt · Answer 1 · 2020-06-24T21:18:27.290

You can do it by applying a function to array's map method that also checks the nested array for the age using find. Since the functions returns undefined for not matching entries, it needs to get rid of these afterwards. Here it is done using .find(Boolean)

This is not a beauty but I hope it helps you:

var mainArray = [{
        'name': 'George',
        'nest': [{ 'id': 1, 'age': 11 }, { 'id': 2, 'age': 22 }],
    },
    {
        'name': 'George',
        'nest': [{ 'id': 2, 'age': 34 }],
    },
    {
        'name': 'Raghu',
        'nest': [{ 'id': 3, 'age': 45 }],
    },
    {
        'name': 'Sudhir',
        'nest': [{ 'id': 4, 'age': 23 }],
    }];

var george22 = mainArray.map((entry) => {
    if (entry.name !== 'George')
        return;
    var nested = entry.nest.find((nested) => nested.age === 22);
    if (!nested)
        return;
    return { name: entry.name, id: nested.id };
}).find(Boolean);

console.log(george22);

Yevhen Horbunkov · Accepted Answer · 2020-06-24T21:16:23.183

Considering the description of expected output, I'm guessing you're looking for a single matching record based on multiple criteria match.

If so, you may check whether Array.prototype.some() source array record fulfills both of desired criteria and assign desired properties (name and id) of the output object accordingly:

const src = [{"name":"George","nest":[{"id":1,"age":11},{"id":2,"age":22}]},{"name":"George","nest":[{"id":2,"age":34}]},{"name":"Raghu","nest":[{"id":3,"age":45}]},{"name":"Sudhir","nest":[{"id":4,"age":23}]}],
                  
      getItemByNameAndAge = (arr, _name,_age) => {
        let name = null, id = null
        src.some(o => 
          o.name == _name && 
          o.nest.some(n => 
            n.age == _age ?
            (id = n.id, name = _name, true) :
            false
          )
        )
        return {name,id}
      }
      
console.log(getItemByNameAndAge(src,'George', 22))

.as-console-wrapper{min-height:100%;}

Out of all answers, I like this the best. Thanks a lot! – George Abraham Jun 25 '20 at 03:30 — George Abraham, Jun 25 '20 at 03:30

score 0 · Answer 3 · answered Jun 24 '20 at 21:44

here is another approach using map

var mainArray = [{ "name":"George", 
                  "nest": [{"id": 1, "age": 11},{"id": 2, "age": 22}]}, 
                { "name":"George", 
                  "nest": [{"id": 2, "age": 34}]}, 
                { "name":"Raghu", 
                  "nest": [{"id": 3, "age": 45}]}, 
                { "name":"Sudhir", 
                  "nest": [{"id": 4, "age": 23}]}]

res=mainArray.map(({...rest})=>({...rest,"nest":rest.nest.length>1?rest.nest[rest.nest.length-1].id:rest.nest[0].id}))
console.log(res)

Filtering array of objects with arrays based on nested value to extract specific fields

3 Answers3