String indexOf()

str.indexOf(search, start)

• str is a string
• search is a string
• start is an integer, index position

indexOf() method returns the index/position of the first occurrence of search string in the string str . if start is provided, the string str from the start position is considered for searching

Examples

1. find index of 'le' search string, in string variable name

let name = 'apple';
let index = name.indexOf('le');
console.log(index);

2. find index of 'an' search string in string variable name from a start position of 10

let name = 'apple banana cherry banana mango';
let start = 10;
let index = name.indexOf('an', start);
console.log(index);

the first occurrence is ignored because the search happens from a start position of 10

3. find index of 'ba' search string in string variable name

let name = 'apple';
let index = name.indexOf('ba');
console.log(index);

since there is no occurrence of search string in the calling string, indexOf() returns -1