JavaScript Loops - Looping Through Maps and Sets

Maps and Sets are important data structures in JavaScript that allow you to store and work with collections of data. In this guide, we'll explore how to loop through Maps and Sets and provide examples to illustrate their usage.

Looping Through a Map

A Map is a collection of key-value pairs, and you can loop through its entries using a for...of loop or the forEach() method. Here's an example:

// Create a Map
const myMap = new Map();
// Add key-value pairs to the Map
myMap.set('name', 'Alice');
myMap.set('age', 30);
myMap.set('city', 'New York');
// Loop through the Map using for...of
for (const [key, value] of myMap) {
    console.log(`${key}: ${value}`);
}
// Loop through the Map using forEach()
myMap.forEach((value, key) => {
    console.log(`${key}: ${value}`);
});
    

In this example, we create a Map, add key-value pairs to it, and then loop through the entries using both the for...of loop and the forEach() method.

Looping Through a Set

A Set is a collection of unique values, and you can loop through its elements using a for...of loop. Here's an example:

// Create a Set
const mySet = new Set();
// Add elements to the Set
mySet.add('apple');
mySet.add('banana');
mySet.add('cherry');
// Loop through the Set using for...of
for (const value of mySet) {
    console.log(value);
}
    

In this example, we create a Set, add elements to it, and then loop through the unique elements using a for...of loop.

Conclusion

Loops are essential for iterating through the elements of collections like Maps and Sets in JavaScript. By understanding how to loop through these data structures, you can efficiently work with and manipulate your data, making your code more robust and readable.

Happy coding with JavaScript Maps and Sets!