how to check string contains characters in javascript code example

Example 1: check for substring javascript

const string = "javascript";
const substring = "script";

console.log(string.includes(substring));  //true

Example 2: javascript string includes

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

Example 3: 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 4: js check if string contains character

"FooBar".includes("oo"); // true

"FooBar".includes("foo"); // false

"FooBar".includes("oo", 2); // false

Example 5: javascript string contains

var string = "foo",
var substring = "oo";

console.log(string.includes(substring));