Sort a Map

I. Problem

Given a map, whose key are integer, sort map entries by the order of its key

Map:[
    [2, 'c'],
    [1, 'a'],   
    [4, 'a'],
    [3, 'e'],
]

res: [
    [1, 'a'],    
    [2, 'c'],
    [3, 'e'],
    [4, 'a'],
]

II. Solution

// Test
let map = new Map([[2, 'c'], [1, 'a'], [4, 'a'], [3, 'e']])

function sortMap(map){
    let resKey = []
    map.forEach((val, key)=>{
        resKey.push(key)
    })
    resKey.sort()
    return resKey.map(item=> [item, map.get(item)])
}
                   
console.log(sortMap(map))

III. Complexity

1. Time: O(N*logN)
2. Space: O(N)