.contains javascript code example
Example 1: check for substring javascript
const string = "javascript";
const substring = "script";
console.log(string.includes(substring)); //true
Example 2: check if word is in string javascript
var str = "Hello world, welcome to the universe.";
var n = str.includes("world");
Example 3: javascript string contains
var string = "foo",
substring = "oo";
console.log(string.includes(substring));
Example 4: 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 5: javascript string contains function
s = "Hello world";
console.log(s.includes("world"));
Example 6: js string contais
const string = "foo";
const substring = "oo";
console.log(string.includes(substring));