JSFiddle - React, Tailwind, and code Playground

JavaScript

var counts = [];
    var str = "11222233344444445666";
    for(var i in str){
        var index = parseInt(str[i])-1
        counts[index] = (counts[index]||0)+1;
    }
    for(var i in counts){
    		var which = 1+parseInt(i);
        var count = counts[i];
        console.log("# of " + which +"'s: "+count);
    }