Triple Equals vs Double Equals in JavaScript

Triple Equals vs Double Equals in JavaScript

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Triple Equals vs Double Equals in JavaScript

In this post, we will give you information about Triple Equals vs Double Equals in JavaScript. Here we will give you detail about Triple Equals vs Double Equals in JavaScript And how to use it also give you a demo for it if it is necessary.

In JavaScript, there are technically 4 different ways of comparing whether 2 values are equal. The 2 most common ways are the == operator and the === operator, also known as abstract equality comparison and strict equality comparison.

Strict Equality With ===

Given 2 values x and y, here’s how JavaScript checks whether x === y:

  1. Check the types of x and y. If they are different types, return false.
  2. If x and y are numbers, first check if either x or y is NaN, and return false if one is NaN. If both x and y are either +0 or -0, return true. Otherwise, check to see if they are the same number.
  3. If x and y are both null or both undefined, return true.
  4. If x and y are both booleans, both strings, or both symbols, compare them by value.
  5. If x and y are both objects, return true if and only if they reference the same object.

In short, here are the important details of ===:

  1. No implicit type coercions. === doesn’t call valueOf() or do anything else to try to convert objects to primitives.
  2. No value is === NaN. You should not use === to check for NaN, use Number.isNaN() instead.
  3. Object comparison is by reference – two different objects can contain the exact same keys, but === will still say they’re different.
const obj1 = { answer: 42 };
const obj2 = { answer: 42 };

obj1 === obj2; // false

Abstract Equality With ==

The == operator uses a more complex abstract equality comparison algorithm to compare whether x and y are equal. Here’s a brief overview:

  1. If x and y are the same type, check if x === y.
  2. If x and y are both either null or undefined, return true.
  3. If x is a number and y is a string, convert y to a number and then compare using ===. Similarly, if x is a boolean or string, and y is a number, convert x to a number.
  4. If x or y is a boolean, convert the other value of a number and compare them.
  5. If x is an object and y is a symbol, string, or number, try to convert x to a primitive using valueOf() and then compare using ===.

Abstract equality comparison is responsible for many of the strange edge cases that JavaScript is so famous for.

'    ' == 0; // true
'    ' == false; // true
({ valueOf: () => 42 }) == 42; // true
({ valueOf: () => 0 }) == false; // true

In general, you should always use === rather than == unless you’re sure
you know what you’re doing. There is one neat functional use for ==: checking for null or undefined (so-called nullish values) with a single check:

// Only true if 'v === null' or 'v === undefined'
v == null;

// Equivalent:
v === null || v === undefined;

Checking if v == null is a more concise way of checking if v is strictly
equal to null or undefined. You may choose to do this if you’re a more
advanced JavaScript developer, but there is no harm in always using ===.

ESLint has a rule to disallow ==unless the right hand side is null,

More Fundamentals Tutorials

  • 3 Patterns to Merge Arrays in JavaScript
  • Convert a BigInt to a Number in JavaScript
  • The parseInt Function in JavaScript
  • The toFixed() Function in JavaScript
  • The Nullish Coalescing Operator ?? in JavaScript
  • Implementing Tuples in JavaScript
  • Convert a JavaScript Enum to a String

JavaScript Fundamentals for Triple Equals vs Double Equals in JavaScript

JavaScript is a programming language that is used to create interactive web pages. It is a client-side scripting language, which means that it runs on the user’s browser. JavaScript can be used to add animation, interactivity, and functionality to web pages.

Here are some of the fundamentals of JavaScript:

  • Variables: Variables are used to store data. They are declared using the var keyword.
  • Data types: JavaScript has a variety of data types, including strings, numbers, booleans, objects, and arrays.
  • Operators: Operators are used to perform operations on data.
  • Control flow statements: Control flow statements allow you to control the order in which your code is executed.
  • Functions: Functions are blocks of code that can be reused.
  • Objects: Objects are used to store data in key-value pairs.
  • Arrays: Arrays are used to store data in a sequential order.
  • Events and event handlers: Events are notifications that are sent by the browser when something happens, such as when the user clicks on an element or moves the mouse over an element. Event handlers are functions that are called in response to an event.
  • DOM manipulation: The Document Object Model (DOM) is a tree-like structure that represents the elements of a web page. JavaScript can be used to manipulate the DOM to change the appearance or behavior of a web page.

These are just some of the fundamentals of JavaScript. There are many other concepts that you can learn as you continue to develop your skills.

Here are some resources that you can use to learn more about JavaScript:

  • Mozilla Developer Network (MDN): The MDN is a great resource for learning about JavaScript. It has a comprehensive reference guide, tutorials, and articles on a wide range of topics.
  • W3Schools: W3Schools is another great resource for learning about JavaScript. It has interactive tutorials and quizzes that can help you learn the basics of the language.
  • JavaScript.info: JavaScript.info is a website that provides in-depth tutorials on JavaScript. It also has a forum where you can ask questions and get help from other JavaScript developers.

I hope this helps for Triple Equals vs Double Equals in JavaScript!

Here are some additional tips for learning JavaScript:

  • Start with the basics: Before you start trying to build complex applications, it’s important to learn the basics of JavaScript. This includes things like variables, data types, operators, and control flow statements.
  • Practice regularly: The best way to learn JavaScript is to practice regularly. Try to find some time each day to work on JavaScript projects.
  • Get help from others: If you get stuck, don’t be afraid to ask for help from others. There are many online forums and communities where you can get help from other JavaScript developers.

With a little practice, you’ll be able to learn JavaScript and start building amazing web applications.

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