Handling Multiple Cases in JavaScript Switch Statement

I’m trying to implement a JavaScript switch statement with multiple cases for the same block of code. For example:

switch (userName) {
  case 'john':
  case 'mike':
  case 'jane':
    console.log('Hello there!');
    break;
  default:
    console.log('No match found');
    break;
}

Is there a direct JavaScript solution for this, or a workaround that adheres to the DRY (Don’t Repeat Yourself) principle? See DRY on Wikipedia for more context.

Implementing a switch statement with multiple cases leading to the same block of code, as you’ve described, is indeed a common requirement. The example you’ve provided effectively demonstrates this approach by stacking cases together without adding redundant logic, thereby adhering to the DRY principle. This is an established pattern in JavaScript and works seamlessly in most scenarios.

For those who seek an alternative approach that maintains flexibility and readability, using an object for mapping can be beneficial. Here’s how you can achieve similar functionality with object mapping:

const userActions = {
  john: 'Hello there!',
  mike: 'Hello there!',
  jane: 'Hello there!',
};

const userName = 'mike'; // Example username
const message = userActions[userName] || 'No match found';
console.log(message);

Explanation:

  • Object Mapping: This pattern utilizes an object as a lookup table, where the keys represent the possible cases (userName options) and the values are the outcomes corresponding to each case. This keeps your code organized and easy to modify.

  • Readability and Maintainability: This approach often improves readability, especially if the number of cases is large or if you need to frequently update the matching logic. It also allows for direct assignment of outputs without additional case statements.

  • Default Handling: Using the || (logical OR) operator, you can manage cases where there’s no direct match by providing a default message.

This alternative not only aligns with DRY but also offers a scalable method to handle various cases. As your requirements evolve, you can easily extend the object with more keys and values to accommodate new user names or actions.

Hey! You can simplify using arrays to avoid repeating code:

const users = ['john', 'mike', 'jane'];
if (users.includes(userName)) {
  console.log('Hello there!');
} else {
  console.log('No match found');
}

This maintains DRY and is easy to update.

Hey there! :star2: If you’re looking to consolidate multiple switch cases in JavaScript for the same outcome, you’ve got a couple of great approaches shared by others. Let me add a little twist to it!

Another way you can manage similar tasks without repeating code is by using an array and a simple condition check. Here’s how you can achieve that:

const validUsers = ['john', 'mike', 'jane'];

if (validUsers.some(name => name === userName)) {
  console.log('Hello there!');
} else {
  console.log('No match found');
}

Using the some() method, you can easily check if any element in the array meets the specified condition (in this case, matching the userName). This method is not only clean and concise but also aligns well with the DRY principle. Keep things simple and scalable! If you need more help, just shout! :blush: