check how many times item exists in array npm code example

Example 1: typescript check if element in array

your_array.includes(the_element)

Example 2: javascript is int in array

[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)