js check if element exists in array] code example

Example 1: how to check if an element already exists in an array in javascript

function includes(arrayOfArrays, item) {
    let array, i, j;
    for(i=0; i<arrayOfArrays.length; ++i) {
        array = arrayOfArrays[i];
        for(j=0; j<array.length; ++j) {
            if(array[j] === item) {
                return true;
            }
        }
    }
    return false;
}

Example 2: check value exist in array javascript

[1, 2, 3].includes(2);     // true
[1, 2, 3].includes(4);     // false
[1, 2, 3].includes(1, 2);  // false (second parameter is the index position in this array at which to begin searching)