Hash Tables & JavaScript Objects

const map = new Map();
map.set(NaN, 'value1');
map.set(NaN, 'value2');
console.log(map.size);

Converts NaN to null
Treats each NaN as unique
Treats all NaN as same key
Map's NaN handling is special because: 1) Treats all NaN values as the same key, 2) Unlike regular equality where NaN ≠ NaN, 3) Only stores one entry for multiple NaN keys, 4) Consistently retrieves values with NaN key, 5) Implements SameValueZero comparison, 6) Different from Object behavior with NaN, 7) Important for reliable key management, 8) Part of ECMAScript specification requirements.
Rejects NaN as key