I need help with replace() method

Question

I need help to solve these 2 problems:

1. When I do string.replace("a","b") it only replaces the first occurrence of the letter I'm looking to replace

2. When replacing something like for example:

var string = "Hello world"
console.log(string.replace("hello", "hey") // Hello world

it does not replace "Hello" because I am looking to replace "hello" but I want it to replace it even if it is "hEllO" what I write

https://code.sololearn.com/cpJygrI36IBM/?ref=app

Answer 1

console.log(string.toLowerCase().replace("hellO".toLowerCase(),"hey"))