string contains value javascript code example

Example 1: javascript string contains

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

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

Example 2: javascript check if character exists in string

// With ES6 MDN docs .includes()
"FooBar".includes("oo"); // true
"FooBar".includes("foo"); // false
"FooBar".includes("oo", 2); // false (2 is the start position for the search)

// E: Not suported by IE - instead you can use the Tilde opperator ~ (Bitwise NOT) with .indexOf()
~"FooBar".indexOf("oo"); // -2
~"FooBar".indexOf("foo"); // 0
~"FooBar".indexOf("oo", 2); // 0 (parameter 2 is the start position for the search)

// Used with a number, the Tilde operator effective does ~N => -(N+1). Use it with double negation !! (Logical NOT) to convert the numbers in bools:
!!~"FooBar".indexOf("oo"); // true
!!~"FooBar".indexOf("foo"); // false
!!~"FooBar".indexOf("oo", 2); // false

Example 3: string.contains javascript

let string = "This string contains pizza";
if(string.includes("pizza") {
	console.log("It's pizza time!");   
}

Example 4: javascript includes

const pets = ['cat', 'dog', 'bat'];

console.log(pets.includes('cat'));
// output: true