js check string in string code example

Example 1: javascript string includes

'Blue Whale'.includes('blue')  // returns false

Example 2: javascript contains substring

var str = "We got a poop cleanup on isle 4.";
if(str.indexOf("poop") !== -1){
	alert("Not again");
}
//use indexOf (it returns position of substring or -1 if not found)

Example 3: if is a string javascript

function isString(x) {
  return Object.prototype.toString.call(x) === "[object String]"
}