me too!

It will never fail since it's javascript. The worst it could get is a NaN value for time.

Nice solution !
If i understand your code correctly , the time complexity of this solution is O(n^2) ?
1.the main while loop
2.the if contains method inside the main loop

You missed the point. There can be multiple unknown true cells since the description specified dead ends.

This is using "loops". Recursion vs iteration. Worst case scenario, it will walk down every dead end before finding the exit.

This solution is actually kind of bad practice due to the contradicting use of booleans. Makes it confusing for anyone coming back to the code. The walked hash essentially treats true as a wall while the map array treats false as a wall. Wall in this sense just means a path that can be ignored.

First iterations would have a lot of characters to check for in the text, but the last ones would run much quicker because you are discarding the already checked characters.

Yeah, I guess you're right, done :)