What are the differences between Map and Object? Why use Map when Object exists?

Map vs Object

Object

• Keys can only be strings or Symbols
• Inherits default prototype properties
• No built-in size property
• Integer keys sorted before string keys

const obj = {};
obj[1] = 'one';
Object.keys(obj); // ['1', ...] (numeric keys first)

Map

• Keys can be any type
• No prototype inheritance
• Built-in size property
• Strictly preserves insertion order

const map = new Map();
map.set('name', 'Alice');
map.set(42, 'answer');
map.size; // 2
map.get(42); // 'answer'

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When to Use Map vs Object

Scenario	Use
Non-string keys	Map
Frequent add/delete	Map
Insertion order matters	Map
Need .size	Map
JSON serialization	Object
Static config	Object