JSFiddle - React, Tailwind, and code Playground

by Khalil Zhang

JavaScript

var obj = {
    name: 'holmes',
    toString: function() {
        return "I'am " + this.name;
    },
    valueOf: function() {
        return 1;
    }
};

alert(obj); //I'am holmes
alert([obj, 'FE'].join(' ')); //I'am holmes FE
alert(obj + 'Holmes'); //1Holmes
alert(obj + 100); //101
alert(++obj); //2
Object.prototype.toString.call([]); // '[object Array]'
Object.prototype.toString.call({}); // '[object Object]'
Object.prototype.toString.call(Number(1)); // '[object Number]'
Object.prototype.toString.call(new Number(1)); // '[object Number]'
Object.prototype.toString.call(Boolean(1)); // '[object Boolean]'
Object.prototype.toString.call(true); // '[object Boolean]'