Iterate an array of arrays for a match from another array

Question

I have an array of arrays, and I would like to iterate this array with the values of another array looking for a match.

let arr1 = [[1,3,5],[2,4,7],[1,5,9]] // [false, false, true]
let arr2 = [1,2,4,5,9] // arr2 contains all values of arr1[2]. return true.

I need it to return truthy falsey if all values in an arr1[i] are present in arr2

for (let i = 0; i < arr1.length; i++) {
  if (arr2.every(arr1[i])) {
    return true
  }
}

mickl · Accepted Answer · 2018-08-10 20:29:01Z

2

You can use .map() with .every()

let arr1 = [[1,3,5],[2,4,7],[1,5,9]];
let arr2 = [1,2,4,5,9];
let result = arr1.map(x => x.every(y => arr2.includes(y)));
console.log(result);

or .filter() if you just want to get matching results:

let arr1 = [[1,3,5],[2,4,7],[1,5,9]];
let arr2 = [1,2,4,5,9];
let result = arr1.filter(x => x.every(y => arr2.includes(y)));
console.log(result);

edited Aug 10, 2018 at 20:29

answered Aug 10, 2018 at 20:25

mickl

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2 Comments

tymeJV Over a year ago

Should technically use a filter over a map - map should always return the same amount of elements in the array it maps over.

mickl Over a year ago

@tymeJV included .filter() in my answer

Nina Scholz · Accepted Answer · 2018-08-10 20:33:03Z

1

You could use Array#some for a single boolean value by using Array#every for each inner array and check array2 with Array#includes.

var array1 = [[1, 3, 5], [2, 4, 7], [1, 5, 9]],
    array2 = [1, 2, 4, 5, 9],
    result = array1.some(a => a.every(v => array2.includes(v)));
    
console.log(result);

Using a Set.

var array1 = [[1, 3, 5], [2, 4, 7], [1, 5, 9]],
    array2 = [1, 2, 4, 5, 9],
    result = array1.some((s => a => a.every(v => s.has(v)))(new Set(array2)));
    
console.log(result);

edited Aug 10, 2018 at 20:33

answered Aug 10, 2018 at 20:27

Nina Scholz

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