How to find a word in a string case insensitive?

Question

JavaScript

"Привет, мир".indexOf("Привет")returns 0, as it should
"Привет, мир".indexOf("привет")
return -1, as it should NOT, replaced "Hello" with "hello" the letter "p" became small
how to make the search case-insensitive?

Answer 1

If you do not need to search for the position where the value was encountered, you can use the regular expression:

var str = 'Привет, мир';
var reg = /привет/i;
reg.test(str) => true

Answer 2

use toLowerCase()
"Hello world".toLowerCase().indexOf("hello")