9 Key New Features of ES6 (ES2015) You Should Know
October 28, 2024
In a previous article, What is ECMAScript? What is it to do with JavaScript?, we discussed the role of ECMAScript as the standard that defines new features and syntax for JavaScript.
Additionally, we mentioned that ES6, also known as ES2015, is a milestone version that introduced many long-awaited syntax improvements and new features. These additions significantly enhance developers' programming experience and efficiency.
In this article, we will focus on introducing some of the key new features of ES6 (ES2015).
9 Key New Features of ES6 (ES2015)
1. let and const Keywords
ES6 introduced the let and const keywords to provide better ways to declare variables. let allows you to declare block-scoped variables, meaning the variable is only accessible within the block it is defined. const is used to declare constants, which are variables that cannot be reassigned after their initial assignment.
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2. Arrow Functions
Arrow functions offer a more concise way to write functions and automatically bind the this keyword to the surrounding context. This helps avoid common issues with the this keyword in JavaScript.
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3. Template Literals
Template literals are enclosed by backticks (```) and allow for easier string concatenation and embedding of variables. They make the code more readable and maintainable.
const name = "ExplainThis";
// Without Template Literals
console.log("Hello " + name + "!");
// Using Template Literals
console.log(`Hello ${name}!`);
4. Destructuring Assignment
Destructuring assignment is a syntax that allows you to extract values from arrays or objects and assign them to variables in a more readable way.
// Using descructuring assignment in an object
const obj = { product: "iphone", price: 20000 };
const { product, price } = obj;
console.log(product); // iphone
console.log(price); // 20000
// Using descruturing assignment in an array
const arr = ["iphone", 20000];
const [product, price] = arr;
console.log(product); // iphone
console.log(price); // 20000
For more details, visit MDN.
5. Default Parameters
Default parameters allow you to set default values for function parameters. This ensures that functions behave as expected even if some arguments are not provided.
function add(a, b) {
return a + b;
}
// Without default values
// If a parameter is missing and the function doesn't handle it
// It can lead to unexpected results
console.log(add(1)); // NaN
// Using default parameters to ensure a and b have default values
function add(a = 0, b = 0) {
return a + b;
}
console.log(add(1)); // 1
6. Spread Operator and Rest Parameters
The spread operator (...) allows you to expand arrays or objects into individual elements. Rest parameters collect multiple arguments into a single array. These features make working with functions and data structures more flexible.
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7. Classes
ES6 introduced the concept of classes, providing a clearer and more familiar syntax for creating objects and handling inheritance. While JavaScript classes are syntactic sugar over its existing prototype-based inheritance, they make the code more organized and easier to understand, especially for those coming from other object-oriented programming languages.
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8. Modules
ES6 provides official support for modules, allowing you to import and export code between different files using the import and export keywords. This promotes better code organization and reuse.
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9. Promises
Promises are a mechanism for handling asynchronous operations in JavaScript. They help avoid "callback hell" by providing a more manageable and readable way to handle asynchronous code, making it easier to work with operations like data fetching or file reading.
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