10 New JavaScript Features in ES2020 That You Should Know

Good news – the new ES2020 features are now finalised! This means we now have a complete idea of the changes happening in ES2020, the new and improved specification of JavaScript. So let’s see what those changes are.

1: BigInt

BigInt is one of the most anticipated features in JavaScript which is now finally here. It actually allows developers to have much greater integer representation in their JS code for data processing for data handling.

At the moment the maximum number you can store as an integer in JavaScript is pow(2, 53) - 1 . But BigInt actually allows you to go even beyond that.

However, you need to have an n appended at the very end of the number, as you can see above. This n denotes that this is a BigInt and should be treated specially by the JavaScript engine (by the v8 engine or whatever engine it is using).

This improvement is not backwards compatible because the traditional number system is IEEE754 (which just cannot support numbers of this size).

2: Dynamic import

Dynamic imports in JavaScript natively give you the option to import JS files dynamically as modules in your application. This is just like how you do it with Webpack and Babel at the moment.

This feature will help you ship on-demand-request code, better known as code splitting, without the overhead of webpack or other module bundlers. You can also conditionally load code in an if-else block if you like.

The good thing is that you actually import a module, and so it never pollutes the global namespace.

3: Nullish Coalescing

Nullish coalescing adds the ability to truly check nullish values instead of falsey values. What is the difference between nullish and falsey values, you might ask?

In JavaScript, a lot of values are falsey, like: empty strings, the number 0, undefined, null, false, NaN, etc.

However, a lot of times you might want to check if a variable is nullish, that is if it is either undefined or null, like when it’s okay for a variable to have an empty string, or even a false value.

In that case, you’ll use the new nullish coalescing operator -> ??

You can clearly see how the OR operator always returns a truthy value, whereas the nullish operator returns a non-nulllish value.

4: Optional Chaining

Optional chaining syntax allows you to access deeply nested object properties without worrying if the property exists or not. If it exists, great! If not, you’ll get undefined returned.

This not only works on object properties, but also on function calls and arrays. Super convenient! Here’s an example:

5: Promise.allSettled

The Promise.allSettled method accepts an array of Promises and only resolves when all of them are settled - either resolved or rejected.

This was not available natively earlier, even though some close implementations like race and all were available. This brings “just run all promises - I don’t care about the results” natively to JavaScript.

6: String#matchAll

matchAll is a new method added to the String prototype which is related to Regular Expressions. This returns an iterator which returns all matched groups one after another. Let’s have a look at a quick example:

7: globalThis

If you wrote some cross-platform JS code which could run on Node as well as in the browser environment as well as inside web-workers, you’d have a hard time getting hold of the global object.

This is because it is window for browsers, global for Node, and self for web workers. If there are more runtimes, they’ll be different for them as well.

So you would have had to have your own implementation of detecting runtime and then using the correct global – that is, until now.

ES2020 brings us globalThis which always refers to the global object, no matter where you are executing your code:

8: Module Namespace Exports

In JavaScript modules, it was already possible to use the following syntax:

import * as utils from './utils.mjs'

However, no symmetric export syntax existed… until now:

export * as utils from './utils.mjs'

This is equivalent to the following:

import * as utils from './utils.mjs'
export { utils }

9: Well defined for-in order

The ECMA specification did not specify in which order for (x in y) should run. Even though browsers implemented a consistent order on their own before now, this has been officially standardized in ES2020.

10: import.meta

The import.meta object was created by the ECMAScript implementation, with a null prototype.

Consider a module module.js

<script type="module" src="module.js"></script>

you can access meta information about the module using the import.meta object.

console.log(import.meta); // { url: "file:///home/user/module.js" }

It returns an object with a url property indicating the base URL of the module. This will either be the URL from which the script was obtained (for external scripts), or the document base URL of the containing document (for inline scripts).

Conclusion

I love the consistency and speed with which the JavaScript community has evolved and is evolving. It is amazing and truly wonderful to see how JavaScript came from a language which was boo-ed on, 10 years go, to one of the strongest, most flexible and versatile language of all time today.

#javascript #web-development #angular #node-js #reactjs

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To-do List App with HTML, CSS and JavaScript

Learn how to create a to-do list app with local storage using HTML, CSS and JavaScript. Build a Todo list application with HTML, CSS and JavaScript. Learn the basics to JavaScript along with some more advanced features such as LocalStorage for saving data to the browser.

HTML:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>To Do List With Local Storage</title>
    <!-- Font Awesome Icons -->
    <link
      rel="stylesheet"
      href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.2.0/css/all.min.css"
    />
    <!-- Google Fonts -->
    <link
      href="https://fonts.googleapis.com/css2?family=Poppins:wght@400;500&display=swap"
      rel="stylesheet"
    />
    <!-- Stylesheet -->
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <div class="container">
      <div id="new-task">
        <input type="text" placeholder="Enter The Task Here..." />
        <button id="push">Add</button>
      </div>
      <div id="tasks"></div>
    </div>
    <!-- Script -->
    <script src="script.js"></script>
  </body>
</html>

CSS:

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}
body {
  background-color: #0b87ff;
}
.container {
  width: 90%;
  max-width: 34em;
  position: absolute;
  transform: translate(-50%, -50%);
  top: 50%;
  left: 50%;
}
#new-task {
  position: relative;
  background-color: #ffffff;
  padding: 1.8em 1.25em;
  border-radius: 0.3em;
  box-shadow: 0 1.25em 1.8em rgba(1, 24, 48, 0.15);
  display: grid;
  grid-template-columns: 9fr 3fr;
  gap: 1em;
}
#new-task input {
  font-family: "Poppins", sans-serif;
  font-size: 1em;
  border: none;
  border-bottom: 2px solid #d1d3d4;
  padding: 0.8em 0.5em;
  color: #111111;
  font-weight: 500;
}
#new-task input:focus {
  outline: none;
  border-color: #0b87ff;
}
#new-task button {
  font-family: "Poppins", sans-serif;
  font-weight: 500;
  font-size: 1em;
  background-color: #0b87ff;
  color: #ffffff;
  outline: none;
  border: none;
  border-radius: 0.3em;
  cursor: pointer;
}
#tasks {
  background-color: #ffffff;
  position: relative;
  padding: 1.8em 1.25em;
  margin-top: 3.8em;
  width: 100%;
  box-shadow: 0 1.25em 1.8em rgba(1, 24, 48, 0.15);
  border-radius: 0.6em;
}
.task {
  background-color: #ffffff;
  padding: 0.3em 0.6em;
  margin-top: 0.6em;
  display: flex;
  align-items: center;
  border-bottom: 2px solid #d1d3d4;
  cursor: pointer;
}
.task span {
  font-family: "Poppins", sans-serif;
  font-size: 0.9em;
  font-weight: 400;
}
.task button {
  color: #ffffff;
  padding: 0.8em 0;
  width: 2.8em;
  border-radius: 0.3em;
  border: none;
  outline: none;
  cursor: pointer;
}
.delete {
  background-color: #fb3b3b;
}
.edit {
  background-color: #0b87ff;
  margin-left: auto;
  margin-right: 3em;
}
.completed {
  text-decoration: line-through;
}

Javascript:

//Initial References
const newTaskInput = document.querySelector("#new-task input");
const tasksDiv = document.querySelector("#tasks");
let deleteTasks, editTasks, tasks;
let updateNote = "";
let count;

//Function on window load
window.onload = () => {
  updateNote = "";
  count = Object.keys(localStorage).length;
  displayTasks();
};

//Function to Display The Tasks
const displayTasks = () => {
  if (Object.keys(localStorage).length > 0) {
    tasksDiv.style.display = "inline-block";
  } else {
    tasksDiv.style.display = "none";
  }

  //Clear the tasks
  tasksDiv.innerHTML = "";

  //Fetch All The Keys in local storage
  let tasks = Object.keys(localStorage);
  tasks = tasks.sort();

  for (let key of tasks) {
    let classValue = "";

    //Get all values
    let value = localStorage.getItem(key);
    let taskInnerDiv = document.createElement("div");
    taskInnerDiv.classList.add("task");
    taskInnerDiv.setAttribute("id", key);
    taskInnerDiv.innerHTML = `<span id="taskname">${key.split("_")[1]}</span>`;
    //localstorage would store boolean as string so we parse it to boolean back
    let editButton = document.createElement("button");
    editButton.classList.add("edit");
    editButton.innerHTML = `<i class="fa-solid fa-pen-to-square"></i>`;
    if (!JSON.parse(value)) {
      editButton.style.visibility = "visible";
    } else {
      editButton.style.visibility = "hidden";
      taskInnerDiv.classList.add("completed");
    }
    taskInnerDiv.appendChild(editButton);
    taskInnerDiv.innerHTML += `<button class="delete"><i class="fa-solid fa-trash"></i></button>`;
    tasksDiv.appendChild(taskInnerDiv);
  }

  //tasks completed
  tasks = document.querySelectorAll(".task");
  tasks.forEach((element, index) => {
    element.onclick = () => {
      //local storage update
      if (element.classList.contains("completed")) {
        updateStorage(element.id.split("_")[0], element.innerText, false);
      } else {
        updateStorage(element.id.split("_")[0], element.innerText, true);
      }
    };
  });

  //Edit Tasks
  editTasks = document.getElementsByClassName("edit");
  Array.from(editTasks).forEach((element, index) => {
    element.addEventListener("click", (e) => {
      //Stop propogation to outer elements (if removed when we click delete eventually rhw click will move to parent)
      e.stopPropagation();
      //disable other edit buttons when one task is being edited
      disableButtons(true);
      //update input value and remove div
      let parent = element.parentElement;
      newTaskInput.value = parent.querySelector("#taskname").innerText;
      //set updateNote to the task that is being edited
      updateNote = parent.id;
      //remove task
      parent.remove();
    });
  });

  //Delete Tasks
  deleteTasks = document.getElementsByClassName("delete");
  Array.from(deleteTasks).forEach((element, index) => {
    element.addEventListener("click", (e) => {
      e.stopPropagation();
      //Delete from local storage and remove div
      let parent = element.parentElement;
      removeTask(parent.id);
      parent.remove();
      count -= 1;
    });
  });
};

//Disable Edit Button
const disableButtons = (bool) => {
  let editButtons = document.getElementsByClassName("edit");
  Array.from(editButtons).forEach((element) => {
    element.disabled = bool;
  });
};

//Remove Task from local storage
const removeTask = (taskValue) => {
  localStorage.removeItem(taskValue);
  displayTasks();
};

//Add tasks to local storage
const updateStorage = (index, taskValue, completed) => {
  localStorage.setItem(`${index}_${taskValue}`, completed);
  displayTasks();
};

//Function To Add New Task
document.querySelector("#push").addEventListener("click", () => {
  //Enable the edit button
  disableButtons(false);
  if (newTaskInput.value.length == 0) {
    alert("Please Enter A Task");
  } else {
    //Store locally and display from local storage
    if (updateNote == "") {
      //new task
      updateStorage(count, newTaskInput.value, false);
    } else {
      //update task
      let existingCount = updateNote.split("_")[0];
      removeTask(updateNote);
      updateStorage(existingCount, newTaskInput.value, false);
      updateNote = "";
    }
    count += 1;
    newTaskInput.value = "";
  }
});

---

Related Videos

Build a Todo list app in HTML, CSS & JavaScript | JavaScript for Beginners tutorial

Build a Todo List App in HTML, CSS & JavaScript with LocalStorage | JavaScript for Beginners

To Do List using HTML CSS JavaScript | To Do List JavaScript

Create A Todo List App in HTML CSS & JavaScript | Todo App in JavaScript

#html #css #javascript

Favorite New Features in ES2020 - JavaScript tutorial

JavaScript’s development had been running at a slower pace ahead of the introduction of ES6 (also known as ECMAScript 2015).Now, in 2020, the latest JavaScript features have been finalized and released as ECMAScript 2020 (or ES2020). While ES2020 does not include as many features as they introduced in ES6, it has introduced a number of useful additions. In this article, I will discuss my favorite new features from ES2020.

Optional Chaining

Optional Chaining syntax allows you to access deeply nested objects without worrying about whether the property exists or not. While working with objects, you must be familiar with an error of this kind:

TypeError: Cannot read property <xyz> of undefined

The above error means that you are trying to access the property of an undefined variable. To avoid such errors, your code will look like this:

Instead of checking each node, optional chaining handles these cases with ease. Below is the same example using optional chaining:

You can also check arrays and functions using Optional Chaining. An example is given below:

---

globalThis

JavaScript is used in a variety of environments such as web browsers, Node.js, Web Workers, and so on. Each of these environments has its own object model and a different syntax to access it. ES2020brings us the **globalThis **property which always refers to the global object, no matter where you are executing your code. This property really shines when you aren’t sure what environment the code is going to run in.

The following is the example of using setTimeout function in Node.js using globalThis:

Below, the same method is used in web browser:

---

Dynamic Imports

Dynamic Imports is one of my favorite feature of ES2020. As the name implies, you can import modules dynamically. Using dynamic imports, the code is delivered via smaller bundles as required (instead of downloading a single large bundle as has been previously required).

When using dynamic imports, the import keywords can be called as a function, which returns a promise. Below is an example of how you can dynamically import a module when the user clicks on a button:

---

Promise.allSettled()

This method returns a promise that resolves after all of the given promises are either fulfilled or rejected. It is typically used where asynchronous tasks do not depend upon one another to complete successfully, as illustrated in the following example:

---

Nullish Coalescing Operator

The syntax for this operator is

let student = {}
let name = student.name ?? ‘John’

This operator will return a Right Hand Side operand when the Left Hand Side operand is either undefined or null. In the example above, the operator will set the value of name as ‘John’ as student.name is undefined.

At first glance this looks exactly the same as a logical OR operator ( || ), however, logical OR operator Right Hand Side operand when Left Hand Side Operand is false (undefined, null, “”, 0, false, NaN). Below is the comparison of both operators:

Chaining Nullish Coalescing Operator ( ?? ) with AND ( && ) or OR ( || ) operators

It’s not possible to chain AND ( && ) and OR ( || ) operators directly with ?? operator. If you need to combine them, then you must wrap && or || operator in the parenthesis

---

Conclusion

The introduction of ES2020’s new features add even more flexibility and power to the constantly evolving JavaScript. This article explored some of my favorite features but there are a number of others that I’d suggest you look into to see what might suit you best. I hope you found this article useful and that you are as excited as I am about using these features!

#javascript #javascript-development #ecmascript-2020 #es2020

JavaScript ES2020 - Awesome New Features!!

In this video we’ll go over all of the new features included in JavaScript ES2020, aka ECMAScript 2020, aka ES11.

These include:
00:00 - Intro
01:12 - String method matchAll
05:17 - Dynamic import()
06:28 - BigInt
08:36 - Promise.allSettled
09:39 - globalThis
10:50 - for…in mechanics
11:14 - Optional chaining
13:31 - Nullish coalescing operator

#javascript #programming #javascript es2020

What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");
</script>

How to comment JavaScript code?

• For single line comment in JavaScript we have to use // (double slashes)
• For multiple line comments we have to use / * – – * /

<script type="text/javascript">

//single line comment

/* document.write("Hello"); */

</script>

Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Hire Dedicated JavaScript Developers -Hire JavaScript Developers

It is said that a digital resource a business has must be interactive in nature, so the website or the business app should be interactive. How do you make the app interactive? With the use of JavaScript.

Does your business need an interactive website or app?

Hire Dedicated JavaScript Developer from WebClues Infotech as the developer we offer is highly skilled and expert in what they do. Our developers are collaborative in nature and work with complete transparency with the customers.

The technology used to develop the overall app by the developers from WebClues Infotech is at par with the latest available technology.

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