Add ability to tag callsigns as worked. Closes #41

webassets/js/spotsbandsandmap.js

@@ -1,5 +1,10 @@
 // Storage for the spot data that the server gives us.
 var spots = []
+// List of people the user has worked. Each entry has the format callsign-band-mode. These can be added to the list by
+// ticking the checkbox on a row of the table, and cleared from the Display menu. Where a row would be added to the
+// table and the callsign-band-mode is in this list, it is shown struck through as already worked. This is persisted
+// to localStorage.
+let worked = []
 
 // Dynamically add CSS code for the band toggle buttons to be in the appropriate colour.
 // Some band names contain decimal points which are not allowed in CSS classes, so we text-replace them to "p".
@@ -118,10 +123,24 @@ function setBandColorSchemeFromUI() {
     window.location.reload();
 }
 
+// Query if a callsign-band-mode combination as has already been worked
+function alreadyWorked(callsign, band, mode) {
+    return worked.includes(callsign + "-" + band + "-" + mode);
+}
+
 // Reload spots on becoming visible. This forces a refresh when used as a PWA and the user switches back to the PWA
 // after some time has passed with it in the background.
 addEventListener("visibilitychange", (event) => {
     if (!document.hidden) {
         loadSpots();
     }
+});
+
+// Startup
+$(document).ready(function() {
+    // Load worked list
+    var tmpWorked = JSON.parse(localStorage.getItem("worked"));
+    if (tmpWorked) {
+        worked = tmpWorked;
+    }
 });