how to access nested object inside map code example

Example 1: js map nested objects

const items = [
  { id: 1, name: 'Nike Air Max 97', inStock: true },
  { id: 2, name: 'Adidas Continental', inStock: true },
  { id: 3, name: 'Adidas Supercourt', inStock: true },
  { id: 4, name: 'Nike Jordan Dunks', inStock: true }
]
// ? Create a new array "itemsCopy" from it using map
// update the Nike Jordans Dunks in the copyArray to 
// have an "inStock" value of false. 
// Make sure using console.log that you have not affected 
// the original items array.
const itemsCopy = items.map(item => {
  if (item.id === 4) {
    return { ...item, inStock: false }
  }
  return { ...item }
})
console.log('og', items)
console.log('new', itemsCopy)

Example 2: javascript map value nested object

function deepMap(obj, mapfn) {
    function recurse(obj) {
        let res = {}
        console.log(JSON.stringify(obj))
        for (const key in obj) {
            const value = obj[key];
            if (value && typeof value === 'object') {
                res[key] = recurse(value);
            } else {
                res[key] = mapfn(value);
            }
        }
        return res
    }
    return recurse(obj);
}
deepMap({'a':1, 'b':{'c':3}}, (val) => val+1) //{'a':2, 'b':{'c':4}}