I’m new to JavaScript and I’m encountering an issue with a coding challenge that involves exchanging two items in an array. Below is my existing code in JavaScript:
/**
* @param {number[]} values
* @return {number[][]}
*/
var generatePermutations = function(values) {
const len = values.length;
const result = [];
const swapAndExplore = (index, current) => {
if (index >= len - 1) {
result.push([...current]);
return;
}
for (let j = index; j < len; j++) {
[current[j], current[index]] = [current[index], current[j]];
swapAndExplore(index + 1, current);
[current[j], current[index]] = [current[index], current[j]];
}
};
swapAndExplore(0, [...values]);
return result;
};
// Example usage
console.log(generatePermutations([1,2,3]));
However, I encountered a runtime error below:
Line 17 in solution.js
[current[j], current[index]] = [current[index], current[j]];
^
TypeError: Cannot set properties of undefined (setting '2')
I used the debugger to analyze the code, and it appeared to be error-free before the runtime issue occurred. Even executing this in the developer console of Chrome resulted in the same error message.
In an attempt to resolve the problem, I added a semicolon after the swap line:
for (let j = index; j < len; j++) {
[current[j], current[index]] = [current[index], current[j]];
swapAndExplore(index + 1, current);
[current[j], current[index]] = [current[index], current[j]];
}
This has left me puzzled, and unfortunately, I couldn’t find a satisfactory explanation from ChatGPT. I would greatly appreciate any help or insights you could share. Thank you!