Creating a Deep Copy of an Object: A Step-by-Step Guide
In the world of programming, the concept of copying an object is a common practice. It allows developers to create identical copies of an object, without altering the original. However, in some cases, a shallow copy may not be enough. This is where the concept of deep copying comes into play.
A deep copy is a method of creating a completely separate copy of an object, including all of its properties and nested objects. This ensures that any changes made to the original object do not affect the new copy. In this article, we will discuss the process of creating a deep copy of an object in JavaScript, using a step-by-step guide.
Step 1: Understanding the Basics
Before we dive into the code, it is important to understand the difference between a shallow copy and a deep copy. In a shallow copy, the new object simply references the values of the original object. This means that any changes made to the original object will also be reflected in the new object. However, in a deep copy, a new object is created with its own set of values. This ensures that any changes made to the original object do not affect the new one.
Step 2: Using the Spread Operator
One of the easiest ways to create a deep copy of an object is by using the spread operator. This operator allows us to spread out the properties of an object into a new object. Let's take a look at an example:
```
// Original Object
const person = {
name: "John",
age: 30,
address: {
city: "New York",
country: "USA"
}
};
// Creating a deep copy using the spread operator
const deepCopy = { ...person };
console.log(deepCopy);
```
In the above code, we have used the spread operator to create a deep copy of the `person` object. This creates a new object with the same properties as the original object. However, the `deepCopy` object is completely separate from the `person` object and any changes made to one will not affect the other.
Step 3: Using JSON.parse() and JSON.stringify()
Another way to create a deep copy of an object is by using the `JSON.parse()` and `JSON.stringify()` methods. Let's take a look at an example:
```
// Original Object
const person = {
name: "John",
age: 30,
address: {
city: "New York",
country: "USA"
}
};
// Creating a deep copy using JSON methods
const deepCopy = JSON.parse(JSON.stringify(person));
console.log(deepCopy);
```
In the above code, we have used the `JSON.parse()` and `JSON.stringify()` methods to create a deep copy of the `person` object. The `JSON.stringify()` method converts the object into a JSON string, and then the `JSON.parse()` method converts it back into an object. This creates a completely separate copy of the object, including all nested objects.
Step 4: Using the Object.assign() Method
The `Object.assign()` method can also be used to create a deep copy of an object. This method takes in two parameters - the target object and the source object. Let's see an example:
```
// Original Object
const person = {
name: "John",
age: 30,
address: {
city: "New York",
country: "USA"
}
};
// Creating a deep copy using Object.assign()
const deepCopy = Object.assign({}, person);
console.log(deepCopy);
```
In the above code, we have used the `Object.assign()` method to create a deep copy of the `person` object. The first parameter is an empty object, which becomes the target object, and the second parameter is the source object. This creates a new object with the same properties as the original object, but they are completely separate from each other.
Step 5: Handling Circular References
One important thing to note while creating a deep copy of an object is to handle circular references. A circular reference occurs when an object has a property that refers back to itself. Let's take a look at an example:
```
// Original Object
const person = {
name: "John",
age: 30,
address: {
city: "New York",
country: "USA"
}
};
// Creating a circular reference
person.self = person;
// Creating a deep copy using the spread operator
const deepCopy = { ...person };
console.log(deepCopy);
```
In the above code, we have created a circular reference by assigning the `person` object to its own `self` property. If we try to create a deep copy of this object using the spread operator, it will result in an infinite loop and eventually
