JS Practice — Built-in Objects

Map Constructor — insertion order

📖 Usage Example

const m1 = new Map()
const m2 = new Map([['x', 1], ['y', 2]])
console.log(m2.size) // → 2

Use the Map constructor to create a new map, optionally passing an array of entries.

Map Constructor

Map preserves insertion order of key-value pairs.

Challenge: Verify that spreading Map keys gives them in insertion order.

💡 Hints (1)