Why does ++[[]][+[]]+[+[]] return the string "10"?

Why does ++[[]][+[]]+[+[]] return the string "10"?

If you've come across the puzzling expression ++[[]][+[]]+[+[]], you might be wondering why it returns the string "10". 🤔 It seems like a nonsensical combination of characters, but fear not! We're here to break it down and explain why this happens.

Understanding the Expression

Let's dissect the expression step by step to understand what's going on:

1. [[]] creates an array with an empty array as its first element.

2. +[] converts the empty array to a number, which is 0. This is because when you try to convert an empty array to a number, JavaScript coerces it to the string "0" and then converts the string to a number.

3. ++[[]][+[]] increments the value at index 0 in the outer array. Since the value at index 0 is 0, after the increment operation, it becomes 1.

4. [+[]] converts the number 1 to an array containing just the number 1.

Finally, we concatenate the two arrays using the + operator. In JavaScript, when you use the + operator with an array and a non-array value, it performs string concatenation. Therefore, the resulting expression is the string "10".

The Essence of the Expression

The core of this expression lies in the manipulation of arrays and their conversions to numbers. By leveraging the coercion rules in JavaScript, we can transform an empty array into the number 0 and perform various operations on it.

Avoiding Confusion

Expressions like ++[[]][+[]]+[+[]] can be misleading and are often used to tease or confuse developers. While they do showcase the quirks and coercion behavior of JavaScript, it's essential to prioritize code readability and maintainability in practical scenarios. Clear and concise code is always preferred over cryptic expressions like this.

Share Your Thoughts and Experiences!

Have you encountered similar mind-bending code snippets before? We'd love to hear about your experiences and impressions. Share your thoughts in the comments below and let's dive into the fascinating world of JavaScript puzzles together!

Remember, it's crucial to approach code and programming challenges with a curious and open mind. Embrace the complexity but strive for simplicity. 💡

So, the next time you encounter an enigmatic expression like ++[[]][+[]]+[+[]], take a step back, break it down, and unveil its mysteries. And if you discover any more perplexing code snippets, feel free to share them with us!

Stay curious, stay coding! 👨‍💻👩‍💻