JavaScript: Check if all arrays contain same value?

Question

I have the following array

// Exmaple
[
   ['morning', 'afternoon'],
   ['morning'],
   ['morning', 'afternoon'],
   ['morning', 'afternoon'],
   ['morning']
]

I may have the same one but with afternoon in every array. I need to check if a given value exists in all arrays, for example if I check for 'morning' it should return true, but if I check for 'afternoon' it should return false because in the example array above not all of them have 'afternoon'

Possible duplicate: https://stackoverflow.com/questions/237104/how-do-i-check-if-an-array-includes-an-object-in-javascript?rq=1 — Tân, Nov 06 '18 at 09:54

score 5 · Accepted Answer · answered Nov 06 '18 at 09:53

5

  array.every(day => day.includes("morning")) // true

answered Nov 06 '18 at 09:53

Jonas Wilms

132,000
20
149
151

score 3 · Answer 2 · answered Nov 06 '18 at 09:53

You can use .every() and .includes() methods:

let data = [
   ['morning', 'afternoon'],
   ['morning'],
   ['morning', 'afternoon'],
   ['morning', 'afternoon'],
   ['morning']
];

let checker = (arr, str) => arr.every(a => a.includes(str));

console.log(checker(data, 'morning'));
console.log(checker(data, 'afternoon'));

score 2 · Answer 3 · answered Nov 06 '18 at 09:53

You can use Array.every and Array.includes

let arr = [['morning', 'afternoon'],['morning'],['morning', 'afternoon'],['morning', 'afternoon'],['morning']];

console.log(arr.every(v => v.includes('morning'))); // true
console.log(arr.every(v => v.includes('afternoon'))); // false

score 1 · Answer 4 · answered Nov 06 '18 at 09:55

1

use .every()

 array.every(d => d.includes("morning")) // true
 array.every(d => d.includes("afternoon")) //false

answered Nov 06 '18 at 09:55

Sooriya Dasanayake

1,106
1
7
14

score 0 · Answer 5 · answered Nov 06 '18 at 10:00

You can use Array.prototype.every() and coerces to boolean the result of Array.prototype.find() which returns the value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned.

Code:

const data = [['morning', 'afternoon'],['morning'],['morning', 'afternoon'],['morning','afternoon'],['morning']];
const checker = (arr, str) => arr.every(a => !!a.find(a => str === a));

console.log(checker(data, 'morning'));
console.log(checker(data, 'afternoon'));

JavaScript: Check if all arrays contain same value?

5 Answers5