JSFiddle - React, Tailwind, and code Playground

by KyleMuir

JavaScript

Array.prototype.numberOfOccurrences = function(valueToFind) { 
    return this.filter(function(item) {
        return item === valueToFind;
    }).length;
}
var a = [1,2,3,3,3,3];
console.log(a.numberOfOccurrences(3));