JavaScript ES6+ Features Every Developer Should Know

JavaScript has evolved massively since ES6 dropped in 2015. Are you still writing JavaScript like it’s 2010? You’re making your life harder than it needs to be. These features actually solve the annoying problems you deal with every day.

React, Vue, Angular — they all lean heavily on ES6+ features. You can’t really avoid learning them anymore. Plus, they help you write less code, introduce fewer bugs, and actually maintain your projects without frustration kicking in.

1. Variable Declarations and Scoping

let and const Replace var

let and const are new ways to declare variables that were introduced in ES6 to replace var. They provide better scoping rules and help prevent common JavaScript. The old var keyword creates confusing behavior. Variables declared with var are function-scoped and get “hoisted,” which leads to unexpected results.

Here’s how you fix it:

Simple rule: Use const by default, let when you need to reassign, and avoid var completely.

2. Template Literals

Concatenating strings with + is painful to read and write. Template literals use backticks and let you embed expressions directly in strings.

3. Destructuring

Instead of writing object.property five times in a row, destructuring lets you extract multiple values at once.

4. Arrow Functions

Arrow functions use => syntax and are perfect for short functions and callbacks.

Arrow functions also handle “this” differently, which solves common JavaScript problems:

5. Default Parameters

Default parameters allow you to set default values for function parameters that will be used if no argument is provided or if undefined is passed.

1. Rest and Spread Operators The … operator works in two ways depending on context.

Rest — collecting multiple elements into an array:

Spread — expanding arrays or objects:

7. Classes

Classes provide a much cleaner syntax than the old prototype approach. They are template for creating objects with shared properties and methods.

The old prototype way was confusing

Classes are so much clearer

8. Enhanced Object Literals

When your property name matches your variable name, you can skip the repetition.

9. Asynchronous Programming

Promises: Handle Async Operations Better

Promises give you a way to handle asynchronous operations without repetitive callbacks.

Async/Await: Write Async That Looks Synchronous

This is possible with these keywords called async and await. They make working with promises easier by allowing you to write asynchronous code that behaves like asynchronous code.

• async before a function means it returns a Promise

• await pauses the function until the Promise resolves

• You can use try/catch for error handling

10. Maps and Sets: Better Data Collections

Maps are like objects but can use any type as keys, not just strings.

Sets store unique values and automatically prevent duplicates.

11. ES6 Modules: Organize Your Code

Split your code into separate files and share functionality between them using import and export statements.

Creating and exporting from a module (math.js):

Importing and using the module (main.js):

12. Optional Chaining: Safe Property Access

The ?. operator lets you safely access nested properties without worrying about null or undefined values.

13. Nullish Coalescing: Better Default Values

The nullish operator works similarly like theOR operator (||). The ?? operator provides a default value only when the left hand side is null or undefined (not for other falsy values like 0, ‘’, or false)

14. BigInt: Handle Very Large Numbers

JavaScript’s regular numbers break down beyond Number.MAX_SAFE_INTEGER. BigInt handles arbitrarily large integers.

Don’t try to learn everything at once. Pick a couple of these features and start using them:

1. Replace all your var declarations with const and let

2. Use template literals instead of string concatenation

3. Try destructuring in your function parameters

4. Convert some callbacks to arrow functions

5. Use async/await for your Promise-based code

6. These features will make your JavaScript more readable and maintainable.

Start with the basics and gradually work your way up to the more advanced features.

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