javascript check character in string code example
Example 1: check if word is in string javascript
var str = "Hello world, welcome to the universe.";
var n = str.includes("world");
Example 2: javascript string contains
var string = "foo",
substring = "oo";
console.log(string.includes(substring));
Example 3: 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 4: javascript string includes
'Blue Whale'.includes('blue') // returns false
Example 5: js check if string contains character
"FooBar".includes("oo"); // true
"FooBar".includes("foo"); // false
"FooBar".includes("oo", 2); // false
Example 6: string.contains javascript
var str = "We got a poop cleanup on isle 4.";
if(str.indexOf("poop") !== -1){
alert("Not again");
}