how to check if an element already exists in an array in javascript 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 if an element is already in an array

private boolean ZitAlInArray(int value, List<Integer> list) {
  return array.indexOf(value) > -1;
}

private boolean zitAlInArray(int[] array, int index) {
		for (int i = 0; i < index; i++) {
			if (array[i] == array[index]) {
				return true;
			}
		} 
		return false;
	}