I got an idex: 10; from terminal of vs code : I was studying regex in javascript . my ide is vs cde and suddenly i got a reply from terminal " [ 'xyz', index: 10, input: 'this is a xyz test' ]"  . what i did was "console.log(value.match(pattern));" and my other code was " let pattern = /xyz/;  let value = 'this is a xyz test';". I want to know what does index : 10, means in the console given by vs code ? I don't even have an idea what to search for.