JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

JavaScript

x = undefined;
    $("div").append("<b>For x=" + x + "</b><br />");
    if(!x) {
       $("div").append("X is not a truthy value<br />");
    }
    if(x == null) {
       $("div").append("X is coerceable null<br />");
    }
    if(x === null) {
       $("div").append("X is null<br />");
    }

    x = "";
    $("div").append("<br /><b>For x=" + x + "</b><br />");
    if(!x) {
       $("div").append("X is not a truthy value<br />");
    }
    if(x == null) {
       $("div").append("X is coerceable to null<br />");
    }
    if(x === null) {
       $("div").append("X is null<br />");
    }

    x = null;
    $("div").append("<br /><b>For x=" + x + "</b><br />");
    if(!x) {
       $("div").append("X is not a truthy value<br />");
    }
    if(x == null) {
       $("div").append("X is coerceable to null<br />");
    }
    if(x === null) {
       $("div").append("X is null<br />");
    }


    x = false;
    $("div").append("<br /><b>For x=" + x + "</b><br />");
    if(!x) {
       $("div").append("X is not a truthy value<br />");
    }
    if(x == null) {
       $("div").append("X is coerceable to null<br />");
    }
    if(x === null) {
       $("div").append("X is null<br />");
    }

    x = 0;
    $("div").append("<br /><b>For x=" + x + "</b><br />");
    if(!x) {
       $("div").append("X is not a truthy value<br />");
    }
    if(x == null) {
       $("div").append("X is coerceable to null<br />");
    }
    if(x === null) {
       $("div").append("X is null<br />");
    }


    x = NaN;
    $("div").append("<br /><b>For x=" + x + "</b><br />");
    if(!x) {
       $("div").append("X is not a truthy value<br />");
    }
    if(x == null) {
       $("div").append("X is coerceable to null<br />");
    }
    if(x === null) {
       $("div").append("X is null<br />");
    }