When working with JavaScript objects, you may need to replace existing keys with new values or delete certain keys altogether. Here's how you can accomplish these tasks effectively.
### Replace Keys in an Object
If you want to replace a key in an object with a new value, you can do so by using the following techniques:
#### Using Bracket Notation
```javascript
let obj = { a: 1, b: 2, c: 3 };
obj['b'] = 5; // Replace key 'b' with value 5
```
#### Using Object Destructuring
```javascript
let obj = { a: 1, b: 2, c: 3 };
let { b, ...rest } = obj;
obj = { ...rest, b: 5 }; // Replace key 'b' with value 5
```
#### Using the Spread Operator
```javascript
let obj = { a: 1, b: 2, c: 3 };
obj = { ...obj, b: 5 }; // Replace key 'b' with value 5
```
### Delete Keys from an Object
If you need to delete a key from an object, you can use the `delete` keyword or create a new object without the key you want to remove:
#### Using the `delete` Keyword
```javascript
let obj = { a: 1, b: 2, c: 3 };
delete obj['b']; // Delete key 'b' from the object
```
#### Creating a New Object
```javascript
let obj = { a: 1, b: 2, c: 3 };
let { b, ...rest } = obj;
obj = { ...rest }; // Create a new object without key 'b'
```
It's important to note that when deleting keys from an object, the original object is modified in place, while replacing keys with new values creates a new object with the updated key-value pairs. Keep these techniques in mind when working with JavaScript objects, and you'll be able to effectively replace and delete keys as needed.
