JavaScript Map is an ordered collection of key-value pairs, where each key is unique. Unlike plain objects, Maps allow any value, including objects, as keys and provide built-in methods for efficient data manipulation. With Maps, we can associate values with specific keys, ensuring fast and reliable access to data. Let’s look at an example:
const fruitPrices = new Map();
fruitPrices.set('apple', 0.99);
fruitPrices.set('banana', 0.49);
fruitPrices.set('orange', 0.79);
console.log(fruitPrices.get('banana')); // 0.49
fruitPrices.delete('apple');
console.log(fruitPrices.has('apple')); // false
console.log(fruitPrices.size); // 2
fruitPrices.clear();
console.log(fruitPrices.size); // 0So Maps are cool and all, but when should you use them? Let’s explore some practical use cases where Maps shine:
Storing and retrieving data based on keys. They are ideal for handling complex data structures, dictionaries, or lookup tables, where key-value relationships play a crucial role.
Uniqueness guarantees that each key occurs only once, making them suitable for tracking unique items or ensuring data integrity.
They preserve the order of key-value pairs, making them useful for scenarios that require maintaining a specific order during iteration, such as maintaining the sequence of actions in an application.