Returning Only Certain Properties From An Array Of Objects In Javascript Duplicate

When working with arrays of objects in JavaScript, there are times when you may need to filter out specific properties and create a new array based on those filtered properties. This process is commonly known as selecting or returning only certain properties from an array of objects. In addition, you may encounter situations where you need to handle duplicates within the original array.

To address this scenario, we can create a function that achieves both tasks efficiently. We will be using JavaScript, specifically leveraging the `map()`, `reduce()`, and `filter()` array methods to extract the desired properties and handle duplicates.

Here's a step-by-step guide to help you achieve this:

1. Define your array of objects:
Let's start by setting up an example array of objects with duplicate entries:

const originalArray = [
       { id: 1, name: 'Apple' },
       { id: 2, name: 'Banana' },
       { id: 1, name: 'Apple' },
       { id: 3, name: 'Cherry' }
   ];

2. Create a function to return only certain properties and eliminate duplicates:

function filterAndRemoveDuplicates(arr, prop) {
       const uniqueIds = [];
       return arr.filter(obj => {
           if (!uniqueIds.includes(obj[prop])) {
               uniqueIds.push(obj[prop]);
               return true;
           }
           return false;
       }).map(obj => ({ [prop]: obj[prop] }));
   }

   const filteredArray = filterAndRemoveDuplicates(originalArray, 'id');

3. Explanation of the function:
- The `filterAndRemoveDuplicates` function takes two parameters: the array of objects `arr` and the property `prop` based on which duplicates are to be removed.
- We use the `filter` method to iterate through the array and only keep objects with unique values of the specified property.
- The `map` method is then employed to extract and return a new array of objects containing only the specified property.

4. Display the resulting array:
You can now log the `filteredArray` to view the output:

console.log(filteredArray);

By following these steps, you can efficiently return only certain properties from an array of objects, eliminating duplicates based on the specified property. This method allows you to streamline your data processing tasks and enhance the efficiency of your JavaScript code.

Feel free to adapt this code snippet to your specific requirements and explore further enhancements to suit your unique use cases. If you have any questions or need further clarification, don't hesitate to reach out for assistance. Happy coding!