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Betterprogramming. I am not sure if it is possible in other programming languages, but in JavaScript, the code snippet below will return true for a certain value of variable a: To know how it works, I would recommend reading this detailed article.


If you have read it, you know it works because of loose equality (i.e. == being used for comparison), which causes JavaScript to coerce the type of one of the values being compared. 18 Tips For Writing JavaScript Code Like A Hero. 42 Tips and Tricks to Write Faster, Better-Optimized JavaScript Code. Improve Angular Performance by understanding Change Detection. The JavaScript Cheatsheet you need in 2021. The Complete Guide to Loops in JavaScript. JavaScript Overview and Practice - Savvy Coders. The Dev Console is a JavaScript REPL ("Read Evaluate Print Loop") that is just waiting for us to interact with it.

JavaScript Overview and Practice - Savvy Coders

Let's give it a try! Remember the DOM? Let's see if we have access to it by typing window.document into the REPL. What's the output? We also have access to data outside of the DOM (in the BOM or "Browser Object Model"). Now we're programming! Mathematic operations are called using operators that we are all familiar with. What's the answer? "JavaScript is " + "FUN" + "!! " "1, 2, 3, and 4 are " + "numbers" + " (sort of)"; Note that all strings have to have quotes (either single or double) around them. In the 'real world', programming implies that you can create a program to be used later, rather than simply typing in commands.

A couple of things to notice about these commands: functions and control flow Now we have bits of data stored in memory for us to manipulate, which is nice. The key to control flow are if, else, and else if statements, built on the Boolean data type. □⚙️ JavaScript Visualized: the JavaScript Engine. JavaScript is cool (don't @ me), but how can a machine actually understand the code you've written?

□⚙️ JavaScript Visualized: the JavaScript Engine

As JavaScript devs, we usually don't have to deal with compilers ourselves. However, it's definitely good to know the basics of the JavaScript engine and see how it handles our human-friendly JS code, and turns it into something machines understand! 🥳 | Note: This post is mainly based on the V8 engine used by Node.js and Chromium-based browsers. Cache API in JavaScript. Learn how to cache resources with… Yield - JavaScript. Top 5 JavaScript secrets. JavaScript is a very... a very special language.

Top 5 JavaScript secrets

Even when you think you know all its secrets, it can still surprise you. Like most things in this World, not all of JS' secrets are really useful. In fact most of them aren't, as everything not well-known by others only leads to confusion. Using secret tips and tricks can make your code run faster or maybe even be smaller, but it'll certainly degrade its readability, which is bad for all the potential reader of your code - including yourself from the future. But, with this little warning out of the way, there's nothing wrong with knowing these secrets - either to be able to read other's cryptic code, or just to show off. So, without further ado, let's explore 5 of what I think are some of the least-known JavaScript secrets! Compose and Pipe in JavaScript. Functional programming: What are… The Magic Behind JavaScript Syntax Shortcuts. At first glance, JavaScript might seem like a pretty easy and straightforward language to code in.

The Magic Behind JavaScript Syntax Shortcuts

But, the deeper you go, the more you'll realize that that's not true. Apart from the general complexity of its prototype-based model, the language also contains numerous syntactic shortcuts and unpredictable tricks that you have to constantly look out for. Global Error Handling in Angular. Learn how to automatically catch all… Blog.bitsrc.

Tube - JavaScript. 11 Frontend tricks that most Frontend Developers don’t know about. Speed Up JavaScript Array Processing. JavaScript. JavaScript (JS) is a lightweight, interpreted, or just-in-time compiled programming language with first-class functions. While it is most well-known as the scripting language for Web pages, many non-browser environments also use it, such as Node.js, Apache CouchDB and Adobe Acrobat. JavaScript is a prototype-based, multi-paradigm, dynamic language, supporting object-oriented, imperative, and declarative (e.g. functional programming) styles. Read more about JavaScript. This section is dedicated to the JavaScript language itself, and not the parts that are specific to Web pages or other host environments.

For information about APIs specific to Web pages, please see Web APIs and DOM.


Execution context. JavaScript can do that? (shorthand techniques) Blog.bitsrc. Conditional JavaScript for Experts - - Medium. Consider the following dummy code snippet for determining the strength of a password: The intent of this code snippet is very simple — check if the password is more than 7 characters long. If it is, then set the strength variable to “Strong”, otherwise set it to “Weak”. The previous code snippet can be shortened to the following: This code snippet does exactly what the previous one does, all in just one line. This looks pretty good already. There is a better way of writing these kinds of if...else conditional expressions — using the conditional operator also called the ternary operator.

The previous code snippet can hence be rewritten using the ternary operator as follows: Although the code snippet using logical operators works in a similar fashion as the snippet using the ternary operator (for this example), it is important to know that they are not substitutes. Converting Object to an Array in JavaScript. You-Dont-Know-JS/ at 1st-ed · getify/You-Dont-Know-JS. Opérateurs binaires - JavaScript. How to Compare Objects in JavaScript. It’s simple to compare primitive values in JavaScript.

How to Compare Objects in JavaScript

Just use any of the available eqality operators, for example the strict equality: Objects, however, are more difficult to compare because they are structured data. 6 Ways to Declare JavaScript Functions. A function is a parametric block of code defined once and called multiple times later.

6 Ways to Declare JavaScript Functions

In JavaScript a function is composed and influenced by many components: JavaScript code that forms the function bodyThe list of parametersThe variables accessible from the lexical scopeThe returned valueThe context this when the function is invokedNamed or an anonymous functionThe variable that holds the function objectarguments object (or missing in an arrow function) This post teaches you six approaches to declare JavaScript functions: the syntax, examples and common pitfalls. Moreover, you will understand when to use a specific function type in certain circumstances.

JavaScript package manager

Application bundlers. JavaScript - Universal Module Definition (UMD) The UMD (Universal Module Definition) pattern is used when our module needs to be imported by a number of different module loaders (e.g.

JavaScript - Universal Module Definition (UMD)

AMD, CommonJS). The pattern itself consists of two parts: An IIFE (Immediately-Invoked Function Expression) that checks for the module loader that is being implemented by the user. This will take two arguments; root (a this reference to the global scope) and factory (the function where we declare our module).An anonymous function that creates our module. This is passed as the second argument to the IIFE portion of the pattern.

What are CJS, AMD, UMD, and ESM in Javascript? - DEV. JavaScript. Tutoriels JavaScript (qui est souvent abrégé en « JS ») est un langage de script léger, orienté objet, principalement connu comme le langage de script des pages web. Mais il est aussi utilisé dans de nombreux environnements extérieurs aux navigateurs web tels que Node.js, Apache CouchDB voire Adobe Acrobat. Le code JavaScript est interprété ou compilé à la volée (JIT). C'est un langage à objets utilisant le concept de prototype, disposant d'un typage faible et dynamique qui permet de programmer suivant plusieurs paradigmes de programmation : fonctionnelle, impérative et orientée objet.

10 Practical JavaScript Tricks - DEV. I'm always on the lookout for new ways to be more efficient.

10 Practical JavaScript Tricks - DEV

And JavaScript is always full of pleasant surprises. 1. Transform the arguments object into an array. The arguments object is an Array-like object accessible inside functions that contains the values of the arguments passed to that function. But it's not like other arrays, we can access the values and we can get the length, but no other array methods can be used on it.

Six things you should know about Objects in JavaScript. Master the JavaScript Interview: What is a Promise? – JavaScript Scene. Ultra small code using Functional Programming. Understanding Closures in JavaScript. A closure is a function that has access to its outer function scope even after the outer function has returned.

Understanding Closures in JavaScript

This means a closure can remember and access variables and arguments of its outer function even after the function has finished. Before we dive into closures, let’s first understand the lexical scope. What is a Lexical Scope? A lexical scope or static scope in JavaScript refers to the accessibility of the variables, functions, and objects based on their physical location in the source code. Levelup.gitconnected. Null and Undefined are both data types in JavaScript. Undefined is a variable that has been declared but not assigned a value. Null as an assignment value. So you can assign the value null to any variable which basically means it’s blank.

Levelup.gitconnected. 7 JavaScript Utility Functions to Improve Your Efficiency. Different browsers have different navigator.useragent. The Modern JavaScript Tutorial. Understanding the Difference Between Reference and Value in JavaScript. Now, what about data types that are not primitives in JavaScript? For example, objects are not primitives, and neither are arrays (which are really just objects, secretly).

Objects are passed by reference. To understand what that means, let’s look at a simple example: const someNumbers = [1, 2, 3];const addNumberToArray = arr => { arr.push(100); return arr;}const otherNumbers = addNumberToArray(someNumbers);console.log(someNumbers);console.log(otherNumbers); The 10 Most Common Mistakes JavaScript Developers Make. Today, JavaScript is at the core of virtually all modern web applications. Underscore.js. Everything you wanted to know about JavaScript scope. Performant JavaScript Best Practices - Level Up Coding. Like any program, JavaScript programs can get slow fast if we aren’t careful with writing our code. In this article, we’ll look at some best practices for writing fast JavaScript programs. DOM manipulation is slow. A Guide to Console Commands. You Might Not Need jQuery.