This post will cover the JavaScript questions I have encountered and have seen during my programming career. They will mainly focus on vanilla JavaScript though there are lots of excellent frameworks out there and many people are using them in their daily work.this keywordthis keyword is an very important but easy to confuse concept in JavaScript since it is always referring to the calling object of the function.1. What will be the output of below code snippet?function User(name) { this.name = name; this.display = function(){ console.log(this.name); }}var user = new User("javas...

Since the release of Java 8, people are excited to see a big feature added to this language which is existing in other languages for a long time -- Lambda expression. The introduction of lambda expression in Java 8 gives people an easy way or a vertical to horizontal way to solve problems. There are many posts on the Internet which shows how to use lambda expression in Java, such as Lambda Quick Start and Java 8 Lambda Expressions Tutorial with Examples. In this post, we will only focus on the this keyword in lambda expression.Unlike anonymous functions, a lambda expression can be considered a...

this in JavaScript is always confusing, it is one of the most frequently seen traps in JavaScript. this is not a good design in JavaScript(You can refer some other design flaws of JavaScript here), since it's lazy binding feature, it can be a global object, the current object or.... Some people even avoid using this in JavaScript.Actually if you master how this works, then you will know how to stay away from these traps. Let's take a look at what this points to in below situations.1. In global scope codesalert(this)//windowthis will point to global object(usually it's window in web browsers) i...

In JavaScript, this is always pointing to the owner of a function or a method.FunctionLet's check out function first.function introduce() {     alert("Hello, I am Laruence\r\n");}For this function, what does this point to? In JavaScript, a global function's owner is the current page, i.e, the window object. Because its a method of the window object if we define a global function. Now you should know the this will point to the window object in the above function.If we check the introduce property of window:var name = "I am Laruence";function introduce() {  &nb...

this is a keyword in JavaScript. It refers to an internal object created automatically when a function executes, it can only be used in a function. For example:        function test(){　　　　this.x = 1;　　}The this keyword will change when a function is called in different situations. However, the general rule is : this refers to the object which calls the function.Next we discuss the use of this in 4 different situations.1. In pure function callThis is the most common use of a function, it is a global call, so the this w...