Labs: Make "give up" require a certain number of seconds (#729)

To encourage people to *try* to do the labs, if they pick
"give up" too soon after loading, we'll instead tell them to
try harder first. It also shows the number of seconds elapsed
(a strong hint that this is timed).

This intentionally does not show the minimum time. The purpose is
to get people to work on the lab, not to encourage them to
game the timer.

Signed-off-by: David A. Wheeler <[email protected]>

docs/labs/checker.js

@@ -15,6 +15,8 @@ let page_definitions = {}; // Definitions used when preprocessing regexes
 let user_solved = false; // True if user has *ever* solved it on this load
 let user_gave_up = false; // True if user ever gave up before user solved it
 
+let startTime = Date.now();
+
 // This array contains the default pattern preprocessing commands, in order.
 // We process every pattern through these (in order) to create a final regex
 // to be used to match a pattern.
@@ -394,6 +396,19 @@ function showAnswer(e) {
     alert(`We were expecting an answer like this:\n${goodAnswer}`);
 }
 
+// "Give up" only shows the answer after this many seconds have elapsed.
+const MIN_DELAY_TIME = 60;
+
+function maybeShowAnswer(e) {
+    let currentTime = Date.now();
+    let elapsedTime = (currentTime - startTime) / 1000; // in seconds
+    if (elapsedTime < MIN_DELAY_TIME) {
+        alert("Try harder! Don't give up so soon. Current time spent (in seconds): " + elapsedTime);
+    } else {
+        showAnswer(e);
+    }
+}
+
 /**
  * Reset form.
  * We have to implement this in JavaScript to ensure that the final
@@ -668,7 +683,7 @@ function initPage() {
         }
     }
     for (let giveUpButton of document.querySelectorAll("button.giveUpButton")) {
-        giveUpButton.addEventListener('click', (e) => { showAnswer(e); });
+        giveUpButton.addEventListener('click', (e) => { maybeShowAnswer(e); });
         if (!giveUpButton.title) {
             giveUpButton.title = 'Give up and show an answer.';
         }