Set and Map provide efficient data storage with unique keys. Here's how to use them.
Set Basics#
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Set Operations#
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Map Basics#
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Map vs Object#
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WeakSet and WeakMap#
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Practical Patterns#
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Set for Array Operations#
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Map for Memoization#
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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.