CODEWITHSUNDEEP
javascript
Himmators
Himmators

Reputation: 15006

Check if any object in array has value true?

I have an array that looks like this simplified:

[{one: false,two: 'cat'},{one: true, two: 'dog'},{one: false, two: 'ball'}]

I want to check if any of the one, values are true. The solution I can think of is something like

var truthness;
array.forEach(function (element, i, array) {
 if(element.one){
    truthness = true
    break;
 }
}

if(truthness){
  //code
}else{
  //other code
}

is there a better way to do this?

Upvotes: 3

Views: 4829

Answers (4)

Andy
Andy

Reputation: 63524

The same as you are doing but maybe a little neater (YMMV), you could use some to check if any of the values are true. The beauty of some is:

If such an element is found, some immediately returns true.

If you're catering for older browsers there's a polyfill at the bottom of that page.

var data = [{one: false,two: 'cat'},{one: true, two: 'dog'},{one: false, two: 'ball'}];
var data2 = [{one: false,two: 'cat'},{one: false, two: 'dog'},{one: false, two: 'ball'}];

function oneIsTrue(data) {
  return data.some(function (el) {
    return el.one;
  });
}

oneIsTrue(data); // true
oneIsTrue(data2); // false

Upvotes: 0

mbcrute
mbcrute

Reputation: 1127

You could also use Array.some:

var arr = [{one: false,two: 'cat'},{one: true, two: 'dog'},{one: false, two: 'ball'}];

var truth = arr.some(function(elem) {
    return elem.one;
});

From MDN:

some executes the callback function once for each element present in the array until it finds one where callback returns a true value. If such an element is found, some immediately returns true. Otherwise, some returns false. callback is invoked only for indexes of the array which have assigned values; it is not invoked for indexes which have been deleted or which have never been assigned values.

Upvotes: 0

Felix Kling
Felix Kling

Reputation: 816282

Arrays have a method .some, which returns true if the callback returns true for any element in the array, or false if it returns false for every element in the array.

var truthness = array.some(function(element) {
    return element.one;
});

Upvotes: 9

David
David

Reputation: 3763

What you are doing would work perfectly one small optimization might be to use a while loop.

var i = array.length;
while (i--)
    if (array[i].one)
        break;

if (i >= 0) {
    //truhness
} else {
    //other code
}

it basically does what you did just with possibly a little faster loop.

Upvotes: 0

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