Modern JavaScript ES2024 Features

JavaScript continues to evolve with new features that make development more efficient and enjoyable. Let's explore some of the latest additions.

Array Grouping

The new Object.groupBy() method makes it easy to group array elements:

const products = [
  { name: 'Laptop', category: 'Electronics', price: 999 },
  { name: 'Shirt', category: 'Clothing', price: 29 },
  { name: 'Phone', category: 'Electronics', price: 599 },
  { name: 'Jeans', category: 'Clothing', price: 79 }
];

const grouped = Object.groupBy(products, (product) => product.category);
// Result: { Electronics: [...], Clothing: [...] }

Temporal API

The new Temporal API provides better date and time handling:

import { Temporal } from '@js-temporal/polyfill';

const now = Temporal.Now.plainDateTimeISO();
const birthday = Temporal.PlainDate.from('1990-05-15');
const age = now.toPlainDate().since(birthday).years;

console.log(`You are ${age} years old`);

Pipeline Operator

The pipeline operator makes function composition more readable:

// Instead of:
const result = fn3(fn2(fn1(value)));

// You can write:
const result = value |> fn1 |> fn2 |> fn3;

Record and Tuple

Immutable data structures for better performance and predictability:

const record = #{ name: 'John', age: 30 };
const tuple = #[1, 2, 3, 4, 5];

// Records and tuples are deeply immutable
const newRecord = #{ ...record, age: 31 };

Pattern Matching

Powerful pattern matching for complex conditional logic:

const getValue = (input) => match (input) {
  when ({ type: 'user', name }) -> `Hello, ${name}!`;
  when ({ type: 'admin', permissions }) -> `Admin with ${permissions.length} permissions`;
  when (Number) if (input > 0) -> `Positive number: ${input}`;
  when (Number) -> `Non-positive number: ${input}`;
  default -> 'Unknown input';
};

Import Assertions

Specify the expected type of imported modules:

import json from './data.json' assert { type: 'json' };
import css from './styles.css' assert { type: 'css' };

Conclusion

These modern JavaScript features continue to push the language forward, making it more powerful and developer-friendly. Stay updated with the latest features to write better code!