In JavaScript, when a variable is declared using the const keyword, it means that the variable is a constant and cannot be reassigned. However, this does not mean that the value itself is immutable. For objects, you can still modify the properties and add new keys without changing the const status of the object.
To add a new key to a const object in JavaScript, you can use the spread operator or the Object.assign method to create a new object with the additional key. Here's an example using the spread operator:
```javascript
const myConstObj = {
existingKey: 'value'
};
const updatedObj = {
...myConstObj,
newKey: 'newValue'
};
```
In this example, we create a new object `updatedObj` by spreading the properties of `myConstObj` and adding a new key-value pair. The original object `myConstObj` remains unchanged and still retains its const status.
Alternatively, you can use the Object.assign method to achieve the same result:
```javascript
const myConstObj = {
existingKey: 'value'
};
const updatedObj = Object.assign({}, myConstObj, { newKey: 'newValue' });
```
Again, the original object `myConstObj` is not modified, and the new object `updatedObj` contains the additional key.
It's important to note that while you can add new keys to a const object in JavaScript, you cannot directly modify the existing keys if the object itself is a primitive value. For example, you cannot directly modify the properties of a const string or number. However, if the const object contains other objects or arrays, you can still modify the properties of those nested objects without changing the const status of the outer object.
In conclusion, adding keys to a const object in JavaScript is possible by creating a new object with the additional key using the spread operator or Object.assign method. This allows you to maintain the immutability of the original const object while still extending its functionality with new keys.
