How to access specific value from a nested array within an object array?

Question

I am trying to get a specific field value from a nested array within an object array. I\'m assuming I\'d use map, but every time I use it in this way I get two empty arrays nest

Answer 1

Since array.find is not available in all browsers yet, and you may not be using a build tool, here is a complete ES5 way. It uses filter and map:

var data = [{ id: 12345678900, name: 'Jasmin', age: 27, hobbies: [{'id': 1221, 'name': 'hiking', 'when': 'anytime'}, { 'id': 9865, 'name': 'eating', 'when': 'all the time' }] }, { id: 223456789001, name: 'Joe', age: 35, hobbies: [{'id': 989, 'name':
'gaming', 'when': 'anytime'}, { 'id': 2355, 'name': 'online gaming', 'when': 'all the time' }]}];


function getHobbiesByName(name) {
  return data.filter(function(person) {
    return (person.name == name);
  })[0].hobbies.map(function(hobby) {
    return hobby.name
  })
}

console.log(getHobbiesByName('Joe'))

Answer 2

A quick function to return an item with the desired property and value of that property :

data = [{id:1,name:'Bob',hobbies:['a','b']},{id:2,name:'Alice',hobbies:['c','d']}];

function getPerson(property,value){
 for(var i=0;i<data.length;i++) if(data[i][property] == value) return data[i];
 return {};
}

And a test :

console.log(getPerson('name','Bob'));
console.log(getPerson('name','Bob').hobbies);

Answer 3

var joe = parentArray.find(function (item) {
    return item.name === 'Joe';
});

if (joe) {
    var joesHobbiesNames = joe.hobbies.map(function (hobbie) {
       return hobbie.name;
    });
}

Or in ES6

var joe = parentArray.find((item) => item.name === 'Joe');

if (joe) {
    var joesHobbiesNames = joe.hobbies.map((hobbie) => hobbie.name);
}