[javascript] How to find index of an object by key and value in an javascript array

Given:

var peoples = [
  { "attr1": "bob", "attr2": "pizza" },
  { "attr1": "john", "attr2": "sushi" },
  { "attr1": "larry", "attr2": "hummus" }
];

Wanted:

Index of object where attr === value for example attr1 === "john" or attr2 === "hummus"

Update: Please, read my question carefully, i do not want to find the object via $.inArray nor i want to get the value of a specific object attribute. Please consider this for your answers. Thanks!

Using jQuery .each()

var peoples = [_x000D_
  { "attr1": "bob", "attr2": "pizza" },_x000D_
  { "attr1": "john", "attr2": "sushi" },_x000D_
  { "attr1": "larry", "attr2": "hummus" }_x000D_
];_x000D_
_x000D_
$.each(peoples, function(index, obj) {_x000D_
   $.each(obj, function(attr, value) {_x000D_
      console.log( attr + ' == ' + value );_x000D_
   });_x000D_
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

Using for-loop:

var peoples = [_x000D_
  { "attr1": "bob", "attr2": "pizza" },_x000D_
  { "attr1": "john", "attr2": "sushi" },_x000D_
  { "attr1": "larry", "attr2": "hummus" }_x000D_
];_x000D_
_x000D_
for (var i = 0; i < peoples.length; i++) {_x000D_
  for (var key in peoples[i]) {_x000D_
    console.log(key + ' == ' + peoples[i][key]);_x000D_
  }_x000D_
}

If you want to check on the object itself without interfering with the prototype, use hasOwnProperty():

var getIndexIfObjWithOwnAttr = function(array, attr, value) {
    for(var i = 0; i < array.length; i++) {
        if(array[i].hasOwnProperty(attr) && array[i][attr] === value) {
            return i;
        }
    }
    return -1;
}

to also include prototype attributes, use:

var getIndexIfObjWithAttr = function(array, attr, value) {
    for(var i = 0; i < array.length; i++) {
        if(array[i][attr] === value) {
            return i;
        }
    }
    return -1;
}

function getIndexByAttribute(list, attr, val){
    var result = null;
    $.each(list, function(index, item){
        if(item[attr].toString() == val.toString()){
           result = index;
           return false;     // breaks the $.each() loop
        }
    });
    return result;
}

You can also make it a reusable method by expending JavaScript:

Array.prototype.findIndexBy = function(key, value) {
    return this.findIndex(item => item[key] === value)
}

const peoples = [{name: 'john'}]
const cats = [{id: 1, name: 'kitty'}]

peoples.findIndexBy('name', 'john')
cats.findIndexBy('id', 1)

Not a direct answer to your question, though I thing it's worth mentioning it, because your question seems like fitting in the general case of "getting things by name in a key-value storage".

If you are not tight to the way "peoples" is implemented, a more JavaScript-ish way of getting the right guy might be :

var peoples = {
  "bob":  { "dinner": "pizza" },
  "john": { "dinner": "sushi" },
  "larry" { "dinner": "hummus" }
};

// If people is implemented this way, then
// you can get values from their name, like :
var theGuy = peoples["john"];

// You can event get directly to the values
var thatGuysPrefferedDinner = peoples["john"].dinner;

Hope if this is not the answer you wanted, it might help people interested in that "key/value" question.

Do this way:-

var peoples = [
  { "name": "bob", "dinner": "pizza" },
  { "name": "john", "dinner": "sushi" },
  { "name": "larry", "dinner": "hummus" }
];

$.each(peoples, function(i, val) {
    $.each(val, function(key, name) {
        if (name === "john")
            alert(key + " : " + name);
    });
});

OUTPUT:

name : john

Refer LIVE DEMO

?