//The lastIndexOf() method returns the index of the last occurrence of a specified text in a string:
let str = "Please locate where 'locate' occurs!";
str.lastIndexOf("locate");
// >> 21
//if you find this answer is useful ,
//upvote ⇑⇑ , so can the others benefit also . @mohammad alshraideh ( ͡~ ͜ʖ ͡°)