Find whether Value in Object exists within an array

Question

I am trying to find whether the value roomTypeFilter exists within an Object inside an array. I then want to perform conditional statements depending whether the value roomTypeFilter exists or not.

Below is my code

function includes(k) {
    for (var i = 0; i < this.length; i++) {
        if (this[i] === k || (this[i] !== this[i] && k !== k)) {
            return true;
        }
    }
    return false;

}
var dayValue = this.ui.dayConstraintList.val();
var arr = [courseTemplate.get('dayConstraints')[dayValue]];
console.log(arr);
arr.includes = includes;
console.log(arr.includes('roomTypeFilter'));

The first console.log returns an Object inside an array.

The second console.log returns false, in this case as roomTypeFilter exists inside the Object I want to return 'true' but I am unsure how to do so, any help would be greatly appreciated.

console.log(!arr.filter(d => d.hasOwnProperty('roomTypeFilter')).length); — Ja9ad335h
– Ja9ad335h, Commented Aug 17, 2016 at 13:17

Ted · Accepted Answer · 2016-08-17 13:17:09Z

1

Instead of using includes, use hasOwnProperty. Take a look here for more information on the hasOwnProperty. It's pretty self-explanatory from its name - it essentially returns a boolean on whether or not the object has a property. I.e., in your case, you would use:

arr[0].hasOwnProperty('roomTypeFilter');

answered Aug 17, 2016 at 13:17

Ted

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4 Comments

mcclosa Over a year ago

When I try console.log(arr[0].hasOwnProperty('roomTypeFilter')); I get Uncaught TypeError: Cannot read property 'hasOwnProperty' of undefined

Ted Over a year ago

Then your arr[0] must be undefined. Whichever object you would like check if it contains the function you're looking for, place that at arr[0]. The syntax is essentially object.hasOwnProperty('function/property')

mcclosa Over a year ago

Ahh yes, the function this is within is called on two different circumstances, it's initially undefined, but defined in another circumstance.

Ted Over a year ago

Great :) Glad i could help, if you have any further questions, let me know

Mladen Ilić · Accepted Answer · 2016-08-17 13:21:46Z

1

You can use hasOwnProperty method to check if object contains roomTypeFilter property.

...
if (this[i].hasOwnProperty(k)) {
    ...
}
...

answered Aug 17, 2016 at 13:21

Mladen Ilić

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Comments

Community · Accepted Answer · 2020-06-20 09:12:55Z

1

You could refactor your includes function to use

array.prototype.some

some() executes the callback function once for each element present in the array until it finds one where callback returns a truthy value... If such an element is found, some() immediately returns true.

Here is an example.

var arr = [
  {
    roomTypeFilter: {
      name: 'foo'
    }
  },
  ["roomTypeFilter", "foo"],
  "roomTypeFilter foo"
]

function includes(arr, k) {
  return arr.some(function(item) {
    return item === Object(item) && item.hasOwnProperty(k);
  })
}

console.log("Does arr includes roomTypeFilter ? - ", includes(arr, 'roomTypeFilter'))

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Aug 17, 2016 at 13:35

DavidDomain

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