JSFiddle - React, Tailwind, and code Playground

JavaScript

Function.prototype.method = function (name, func) {
    this.prototype[name] = func;
    return this;
};

Number.method('integer', function () {
    return Math[this < 0
        ? "ceiling"
        : "floor"](this);
});

console.log((-10 / 3).integer());