ECMAScript 6+ (ES6+) – Using the let keyword

ECMAScript 6+ (ES6+) – Using the let keyword

ECMAScript 6, also known as ES6 or ES2015, introduced several new features to JavaScript to make the language more powerful and easier to work with. One of the most notable additions in ES6 is the introduction of the let keyword for declaring variables.

Unlike the var keyword, which has been traditionally used to declare variables in JavaScript, the let keyword has block scope. This means that variables declared with let are only accessible within the block they are defined in, whether it’s a function, loop, or any other block.

Let’s look at an example to understand how the let keyword works:

function flashify_example() {
    let message = "Hello, World!";
    console.log(message); // Output: Hello, World!
}

console.log(message); // Throws ReferenceError: message is not defined

In the above example, the variable message is declared using let inside the flashify_example function. This variable is only accessible within the function and trying to access it outside the function will result in a ReferenceError.

Using the let keyword helps prevent variable hoisting and accidental re-declarations, making your code more predictable and less error-prone.

It’s important to note that variables declared with let are not hoisted to the top of their scope like variables declared with var. This can sometimes lead to temporal dead zones where variables are accessed before they are declared, resulting in a ReferenceError.

Overall, the let keyword provides a more reliable and predictable way of declaring variables in JavaScript, and it’s recommended to use it over var in modern ES6+ code.