Please write a JavaScript function that takes in two strings as parameters and returns the longest common prefix found between them. The function should return an empty string if no common prefix is found. Please ensure that the function uses proper coding conventions and follows best practices, including error handling and appropriate variable naming.
user
Here's one possible solution to the problem:

```
function longestCommonPrefix(str1, str2) {
  // Handle input validation
  if (!str1 ||!str2 || str1.length === 0 || str2.length === 0) {
    return '';
  } else {
    const len = Math.min(str1.length, str2.length);
    let prefix = '';

    for (let I = 0; I < len; i++) {
      if (str1[i] === str2[i]) {
        prefix += str1[i];
      } else {
        break;
      }
    }

    return prefix;
  }
}

// Example usage:
console.log(longestCommonPrefix('flower', 'flow')); // Expected output: 'fl'
console.log(longestCommonPrefix('apple', 'app')); // Expected output: ''
```

The function first handles null or empty input by returning an empty string. It then calculates the length of the shorter string between the two input strings, and initializes a prefix variable to an empty string.

It then iterates through the characters of both strings up to the shorter string length, comparing each character and adding it to the prefix if they match. If they do not match, it breaks out of the loop.

Finally, the function returns the prefix. If no common prefix is found, the function returns an empty string.

Note: This solution assumes that the input strings are not empty. If you want to allow for empty strings, you would need to add additional input validation to handle that case.
assistant
Please write a JavaScript function that takes in two strings as parameters and returns the longest common prefix found between them. The function should return an empty string if no common prefix is found. Please ensure that the function uses proper coding conventions and follows best practices, including error handling and appropriate variable naming.
user
Here is a JavaScript function that takes in two strings and returns the longest common prefix between them:

```javascript
function longestCommonPrefix(str1, str2) {
  if (!str1 || !str2) {
    throw new Error('Both parameters must be strings.');
  }

  let prefix = '';
  const len = Math.min(str1.length, str2.length);

  for (let I = 0; I < len; i++) {
    if (str1[i] === str2[i]) {
      prefix += str1[i];
    } else {
      break;
    }
  }

  return prefix;
}
```

In this function, we first ensure that both parameters are strings by checking if they are falsy values. If either parameter is not a string, we throw an error using the `Error()` constructor.

Next, we initialize an empty string `prefix` to hold the common prefix, and we use the `Math.min()` function to get the length of the shorter of the two input strings. We use this value in our `for` loop to iterate through both strings up to the length of the shorter string.

Inside the loop, we use an `if` statement to compare the characters at the current index of each string. If they match, we append that character to the `prefix` variable. If they don't match, we break out of the loop, as we have found the longest common prefix.

Finally, we return the `prefix` variable, which will contain either the longest common prefix or an empty string if no prefix was found.
assistant