String lastIndexOf()
str.lastIndexOf(search, start)
str
is a stringsearch
is a stringstart
is an integer, index position
lastIndexOf() method returns the index/position of the last occurrence of search
string in the string str
. searching happens from the trail end of the string str
. if start
is provided, searching the string str
happens from that index at the end of the string str
Examples
1. find index of last occurrence of 'banana'
search string, in string variable name
let name = 'apple banana cherry banana mango';
let index = name.lastIndexOf('banana');
console.log(index);
2. find index of last occurrence of 'banana'
search string in string variable name
searching from from an index of 10
at the trailing end of the string
let name = 'apple banana cherry banana mango';
let start = 10;
let index = name.lastIndexOf('banana', start);
console.log(index);
the last occurrence of the search string 'banana'
is ignored because the search happens from a position of 10 from the end
3. find index of last occurrence of 'banama'
search string in string variable name
let name = 'apple';
let index = name.lastIndexOf('banana');
console.log(index);
since there is no occurrence of search string in the calling string, lastIndexOf()
returns -1