how to check if item in array javascript code example

Example 1: js test if array

if(Array.isArray(myVarToTest)) {
	// myVatToTest is an array
} else {
	// myVarToTest is not an array
}

Example 2: how to check if item is in list js

var myList=["a", "b", "c"];
mylist.includes("d")//returns true or false