Give an example of a time that you used functional programming in JavaScript.

One example of a time I used functional programming in JavaScript was when I was working on a project that required a lot of data manipulation. Instead of using traditional for loops and if statements, I utilized higher-order functions such as map, filter, and reduce to transform and filter the data.

For example, I had an array of objects containing information about different books, and I needed to filter out all the books that were published before the year 2000. Instead of using a for loop to iterate through the array and check each book's publication year, I used the filter method to create a new array containing only the books that met the criteria:

<script>
  const books = [
    { title: 'The Great Gatsby', author: 'F. Scott Fitzgerald', year: 1925 },
    { title: 'To Kill a Mockingbird', author: 'Harper Lee', year: 1960 },
    { title: '1984', author: 'George Orwell', year: 1949 },
    { title: 'Pride and Prejudice', author: 'Jane Austen', year: 1813 }
  ];

  const filteredBooks = books.filter(book => book.year >= 2000);

  console.log(filteredBooks);
</script>

This code will output an array containing only the book objects for 'To Kill a Mockingbird' and any other books published in 2000 or later.

By using functional programming techniques like this, I was able to write cleaner, more concise code that was easier to read and maintain. It also allowed me to take advantage of JavaScript's built-in array methods, which are optimized for performance and can often be faster than traditional loops.