Set and Map provide efficient data storage with unique keys. Here's how to use them.
Set Basics
Set Operations
Map Basics
Map vs Object
WeakSet and WeakMap
Practical Patterns
Set for Array Operations
Map for Memoization
Best Practices
When to Use Set:
✓ Need unique values
✓ Fast membership testing
✓ Set operations (union, intersection)
✓ Removing duplicates
When to Use Map:
✓ Key-value pairs with non-string keys
✓ Need insertion order
✓ Frequent additions/deletions
✓ Need size property
When to Use WeakMap/WeakSet:
✓ Object references as keys
✓ Need garbage collection
✓ Storing private data
✓ Caching computed values
Performance:
✓ O(1) for add, delete, has operations
✓ Use Maps over objects for dynamic keys
✓ Consider WeakMap for large datasets
✓ Avoid JSON.stringify for complex keys
Conclusion
Set and Map provide efficient, purpose-built data structures for unique values and key-value pairs. Use Set for uniqueness and membership testing, Map for flexible key types and ordered entries. WeakSet and WeakMap enable garbage collection for object-keyed data.