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Wonka
Wonka

Reputation: 8674

Javascript - Find 2 items in array?

Using find in Javascript, how can I find 2 items 10 and 18 from the array?

var ages = [3, 10, 18, 20];
ages.find(age => age === 10); // works on one item, returns 10
ages.find(age => age === (10 || 18)); // does not return 10 and 18

Upvotes: 2

Views: 1722

Answers (5)

Simon Tran
Simon Tran

Reputation: 2070

The accepted answers are fine, but they are slow if the arrays are big.

If you only need to find the first 2 items that match, you can use this solution:

let a = null, b = null;
for (let age of ages) {
  if (age === 10) {
    a = age
  }
  else if(age === 18){
    b = age
  }

  if(a != null && b != null){
    break;
  }
}

In the worst case, it will iterate the ages array entirely once.

Upvotes: 0

KevBot
KevBot

Reputation: 18888

I would create another array that holds the possible ages you are looking for. This is going to be easier to read and maintain than or statements.

var ages = [3, 10, 18, 20];
var criteria = [10, 18];

let found = ages.filter(age => criteria.includes(age));
console.log(found);

As pointed out by @Flavio Ochoa, Array.includes may not be supported in legacy browsers. If you're worried about support, or are not using a polyfill for Array.includes, you can just use Array.indexOf instead:

ages.filter(age => criteria.indexOf(age) > -1);

Upvotes: 5

Abhinav Galodha
Abhinav Galodha

Reputation: 9878

You can make use of the filter method which returns the elements which matches the predicate.The filter() method creates a new array with all elements that pass the test implemented by the provided function.

The find method returns the first element in the array that satisfies the condition. So, using find, you wouldn't be able to return more than 1 element.

Also, the comparison is wrong in your code,
instead of age === (10 || 18)
use age === 10 || age === 18)

var ages = [3, 10, 18, 20];
var result = ages.filter(age => age === 10 || age === 18);
console.log(result);

Upvotes: 5

Nina Scholz
Nina Scholz

Reputation: 386550

First,

age === (10 || 18)

is wrong (it checks only age === 10), you need 

age === 10 || age === 18

for checking, second use Array#filter to get an array with the result.

var ages = [3, 10, 18, 20];
console.log(ages.filter(age => age === 10 || age === 18));

Upvotes: 2

Mike Cluck
Mike Cluck

Reputation: 32511

You can't. At least not with just one call.

(emphasis mine)

The find() method returns a value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned.

Source

A better way of approaching this would be to use filter.

var ages = [3, 10, 18, 20];
console.log(ages.filter(age => age === 10 || age === 18));

Upvotes: 1

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