Serialization and Deserialization

What is Serialization?

Serialization is the process of converting in-memory data (objects, classes, structures) into a format that can be sent over the network or stored.

Common formats:

JSON
XML
Protobuf
MessagePack

Example: A JavaScript object → JSON string

What is Deserialization?

Deserialization is the reverse process.

It converts the received data back into a usable in-memory object.

Example: JSON string → JavaScript object

Serialization (Object → JSON)

// JavaScript/TypeScript object
const user = {
  id: 1,
  name: 'John Doe',
  email: 'john@example.com',
  active: true,
  createdAt: new Date('2024-01-01'),
  preferences: {
    theme: 'dark',
    notifications: true,
  },
}

// Serialize to JSON string
const json = JSON.stringify(user, null, 2)
console.log(json)
// Output:
// {
//   "id": 1,
//   "name": "John Doe",
//   "email": "john@example.com",
//   "active": true,
//   "createdAt": "2024-01-01T00:00:00.000Z",
//   "preferences": {
//     "theme": "dark",
//     "notifications": true
//   }
// }

Deserialization (JSON → Object)

// JSON string from API/file
const json = '{"id":1,"name":"John Doe","email":"john@example.com"}'

// Deserialize to JavaScript object
const user = JSON.parse(json)
console.log(user.name) // "John Doe"
console.log(user.email) // "john@example.com"

// Handle parsing errors
try {
  const data = JSON.parse(jsonString)
  return data
} catch (error) {
  console.error('Invalid JSON:', error)
  return null
}

Why Serialization is Needed

Networks can only transfer bytes, not objects
Different systems use different languages
Ensures data is portable, structured, and readable

Data Flow (High Level)

Deserialization on the Receiver Side

Bits are received from the network
Data moves up the OSI layers
Presentation layer deserializes the data
Application layer uses the object

In Simple Words

Serialization = object → bytes (send)
Deserialization = bytes → object (use)
OSI model defines where this transformation logically happens

One-Line Interview Answer

Serialization converts application data into transferable formats at the presentation layer, while deserialization reconstructs it back for application use.

Serialization and Deserialization

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