If statement in an object in JavaScript

Question

I have this object and I want to return a value when the field_id is equal to 40. How can I do this? In this case I want to return 111

  myObj = [{
   id: 11,
   company_id: 1,
   field_id: 7,
   value: 700,
},
  {
   id: 12,
   company_id: 1,
   field_id: 40,
   value: 111,
},
  {
   id: 13,
   company_id: 1,
   field_id: 41,
   value: 222,
 }]

So loop over and find it. – epascarello May 29 '18 at 19:26 — epascarello, May 29 '18 at 19:26

score 1 · Answer 1 · answered May 29 '18 at 19:28

1

for(item of myObj) { if(item.field_id == 40) return item.value; }

answered May 29 '18 at 19:28

Boric

822
7
26

score 1 · Answer 2 · 2018-05-29T20:08:32.837

// Array with objects
myArr = [{
    id: 11,
    company_id: 1,
    field_id: 7,
    value: 700,
  },
  {
    id: 12,
    company_id: 1,
    field_id: 40,
    value: 111,
  },
  {
    id: 13,
    company_id: 1,
    field_id: 41,
    value: 222,
  }
];

myFilter = (arr, key, value, output) => arr.filter(o => o[key] === value).map(r => r[output]);

// Result is an array (if several solutions)
console.log(myFilter(myArr, "field_id", 40, "value"));

score 0 · Answer 3 · answered May 29 '18 at 19:27

0

You need to loop through the array

var i;
for (i = 0; i < myObj.length; i++) { 
    if (myObj[i].field_id == 40) {
        return myObj[i].value
     }
}

answered May 29 '18 at 19:27

Sacha

322
1
8

This will, of course, continue iterating over the array even after the match has been found. – Kevin Boucher May 29 '18 at 19:28
is there a way to do it without using for loop? maybe using .map? @sacha – Lizz Parody May 29 '18 at 19:29
1

No it shouldn't because of the `return` – Sacha May 29 '18 at 19:30
@Sacha fair point. – Kevin Boucher May 29 '18 at 19:30
@LizParody I am not familiar with `map` maybe you can do it that way also – Sacha May 29 '18 at 19:31
@LizParody : map is still an iterative process, i.e. performs a loop – fnostro May 29 '18 at 19:35
@LizParody, also you are dealing with an array of objects, granted a small one but in general... "for" loops are faster than "foreach" loops – fnostro May 29 '18 at 19:38
Map and Filter need to be used if you really want to go the functional route. It would be an overkill anyways. For ex. like below. var valID = myObj.map(function getValue (myObj) {if(myObj.field_id == 40) { return myObj.value; }}).filter(function getValue1(myObj) {return myObj}); console.log(valID); – Sesha Kiran May 29 '18 at 20:46

If statement in an object in JavaScript

3 Answers3