This code uses a recursion algorithm - dfs - to create a list of parentheses. The algorithm works as follows:

First, it checks to see if left and right are equal - if they are, then the parentheses are created and the string "(" is appended to the result.

Next, it checks to see if left is greater than 0 - this is done because the parentheses will be created at the leftmost and rightmost positions, depending on the value of left .

If left is greater than 0, then dfs() is called with left - 1 as the first parameter, right as the second parameter, and the string "(" is appended to the result.

If right is greater than left, then dfs() is called with left, right - 1 as the first parameter, and the string ")")" is appended to the result.

```
const generateParenthesis = (n) => {
const result = [];
const dfs = (left, right, str) => {
if (left === 0 && right === 0) {
result.push(str);
return;
}
if (left > 0) {
dfs(left - 1, right, str + "(");
}
if (right > left) {
dfs(left, right - 1, str + ")");
}
};
dfs(n, n, "");
return result;
};
```