Basics

To create a copy of an immutable object in JavaScript, you can use the Object.assign() method or the spread operator (...). These methods allow you to create a new object with the properties of the original object and then modify the new object as needed.

For example:

const person = {
  name: 'John',
  age: 30
};

// Using Object.assign()
const personCopy1 = Object.assign({}, person, { name: 'Jane' });

// Using the spread operator
const personCopy2 = { ...person, name: 'Jane' };

console.log(personCopy1); // { name: 'Jane', age: 30 }
console.log(personCopy2); // { name: 'Jane', age: 30 }

To update an immutable object, you can create a copy of the object with the desired changes, and then use Object.freeze() or Object.seal() to prevent the object from being modified further.

For example:

const person = {
  name: 'John',
  age: 30
};

const updatedPerson = Object.freeze({ ...person, age: 31 });

console.log(updatedPerson); // { name: 'John', age: 31 }

To delete a property from an immutable object, you can create a copy of the object with the desired property removed.

For example:

const person = {
  name: 'John',
  age: 30,
  address: '123 Main St'
};

const updatedPerson = Object.freeze({
  ...person,
  address: undefined
});

console.log(updatedPerson); // { name: 'John', age: 30 }

It's also possible to use a library like Immutable.js, which provides methods for creating, updating, and deleting properties on immutable objects.