javascript check char in string code example

Example 1: find char in string javascript

var str = "Hello world, welcome to the universe.";

var n = str.indexOf("e");

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: js check if string contains character

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

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

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

Example 4: js string contains

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

console.log(string.indexOf(substring) !== -1);

Example 5: js check if string contains character

if (your_string.indexOf('hello') > -1)
{
  alert("hello found inside your_string");
}