Exercise 16: Storage Migration Helper
Problem Statement
Function `migrateStorage(oldKey, newKey, transform)` banao jo old key se new key me data migrate kare.
Example: migrateStorage("old", "new", (v) => v * 2)
Sample Output:
migrateStorage("old", "new", (v) => v * 2)
// Migrates and transforms dataSolution
const migrateStorage = (oldKey, newKey, transform) => {
const oldValue = localStorage.getItem(oldKey);
if (oldValue) {
const transformed = transform(JSON.parse(oldValue));
localStorage.setItem(newKey, JSON.stringify(transformed));
localStorage.removeItem(oldKey);
}
};Explanation
Overall Goal:
- Storage data ko migrate karna.
Real world:
- Data migration: key changes.
- Upgrades: data transformation.