Map and Set in JavaScript

Short summary

Map and Set are ES6 data structures that solve real limitations of objects and arrays for specific use cases. Maps support keys of any type (strings, numbers, objects), preserve insertion order, and provide instant size tracking instead of requiring Object.keys().length workarounds. Sets automatically enforce uniqueness by rejecting duplicates, work with any value type, and integrate cleanly with modern JavaScript iteration patterns—both are production-ready tools every developer should reach for when basic structures don't fit.

• •Map enables non-string keys (numbers, objects, booleans) and maintains insertion order with built-in .size property
• •Set automatically eliminates duplicates while preserving insertion order, enabling one-line deduplication with [...new Set(array)]
• •Both outperform objects and arrays in specific scenarios: Map for typed key-value pairs, Set for unique collections

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