JSFiddle - React, Tailwind, and code Playground

JavaScript

var str="hello how are you r  u fineOr not .Why u r not fine.Please tell wats makes u notfiness";
var splitStr=str.split(" ");
splitStr.filter(function(word,index){
    if(word.match(/fine/g)){
        /*you may also store this in a data structure e.g. array*/
        console.log(index);
        return true;
    }else{
        return false;
    }
});