JSFiddle - React, Tailwind, and code Playground

JavaScript

var OneInstance = function(numberAdd) {
			if(this.numbers === undefined) this.numbers = [];
			this.numbers.push(numberAdd);
			this.showNumbers = function() {
				alert(this.numbers);
			}
			return this;
		}
		OneInstance(1).showNumbers();
		OneInstance(1).showNumbers();