diff --git a/src/js/about.ts b/src/js/about.ts
index 7335e33..85d69d5 100644
--- a/src/js/about.ts
+++ b/src/js/about.ts
@@ -4,38 +4,39 @@
  * Set up event listeners to open and close the about popup.
  */
 const setUpAbout = () => {
-  const aboutElement: HTMLElement | null =
-    document.querySelector(".about-text-popup");
+  const aboutElement = document.querySelector(".about-text-popup");
   const infoButton = document.querySelector(".header-about-icon-container");
-  if (infoButton && aboutElement) {
-    infoButton.addEventListener("click", () => {
-      aboutElement.style.display =
-        aboutElement.style.display !== "block" ? "block" : "none";
-    });
+  if (
+    !(aboutElement instanceof HTMLElement) ||
+    !(infoButton instanceof HTMLElement)
+  )
+    return;
 
-    // closes window on clicks outside the info popup
-    window.addEventListener("click", (event: MouseEvent) => {
-      const clickTarget = event?.target as Element;
-      if (
-        !infoButton.contains(clickTarget) &&
-        aboutElement.style.display === "block" &&
-        !aboutElement.contains(clickTarget)
-      ) {
-        aboutElement.style.display = "none";
-        infoButton.classList.toggle("active");
-      }
-    });
+  infoButton.addEventListener("click", () => {
+    aboutElement.style.display =
+      aboutElement.style.display !== "block" ? "block" : "none";
+  });
 
+  // closes window on clicks outside the info popup
+  window.addEventListener("click", (event) => {
+    if (
+      event.target instanceof Element &&
+      !infoButton.contains(event.target) &&
+      aboutElement.style.display === "block" &&
+      !aboutElement.contains(event.target)
+    ) {
+      aboutElement.style.display = "none";
+      infoButton.classList.toggle("active");
+    }
+  });
+
+  const aboutClose = document.querySelector(".about-close");
+  if (!(aboutClose instanceof HTMLElement)) return;
+  aboutClose.addEventListener("click", () => {
     // Note that the close element will only render when the about text popup is rendered.
     // So, it only ever makes sense for a click to close.
-    const aboutClose: HTMLAnchorElement | null =
-      document.querySelector(".about-close");
-    if (aboutClose) {
-      aboutClose.addEventListener("click", () => {
-        aboutElement.style.display = "none";
-      });
-    }
-  }
+    aboutElement.style.display = "none";
+  });
 };
 
 export default setUpAbout;
diff --git a/src/js/setUpSite.ts b/src/js/setUpSite.ts
index d0e11c5..9527d77 100644
--- a/src/js/setUpSite.ts
+++ b/src/js/setUpSite.ts
@@ -232,36 +232,32 @@ const setUpCitiesLayer = async (
 
   // Set up map to update when city selection changes.
   const cityToggleElement = document.getElementById("city-dropdown");
-  if (cityToggleElement instanceof HTMLSelectElement) {
-    cityToggleElement.addEventListener("change", async () => {
-      const cityId = cityToggleElement.value;
-      const { layer } = cities[cityId];
-      if (layer) {
-        snapToCity(map, layer);
-      }
-    });
+  if (!(cityToggleElement instanceof HTMLSelectElement)) return;
+  cityToggleElement.addEventListener("change", async () => {
+    const cityId = cityToggleElement.value;
+    const { layer } = cities[cityId];
+    if (layer) {
+      snapToCity(map, layer);
+    }
+  });
 
-    // Set up map to update when user clicks within a city's boundary
-    allBoundaries.addEventListener("click", (e) => {
-      const currentZoom = map.getZoom();
-      if (currentZoom > 7) {
-        const cityId = e.sourceTarget.feature.properties.id;
-        cityToggleElement.value = cityId;
-        const { layer } = cities[cityId];
-        if (layer) {
-          snapToCity(map, layer);
-        }
-      }
-    });
+  // Set up map to update when user clicks within a city's boundary
+  allBoundaries.addEventListener("click", (e) => {
+    const currentZoom = map.getZoom();
+    if (currentZoom <= 7) return;
+    const cityId = e.sourceTarget.feature.properties.id;
+    cityToggleElement.value = cityId;
+    const { layer } = cities[cityId];
+    if (layer) {
+      snapToCity(map, layer);
+    }
+  });
 
-    // Load initial city.
-    const cityId = cityToggleElement.value;
-    setUpAutoScorecard(map, cities, parkingLayer);
-    snapToCity(map, cities[cityId].layer);
-    setScorecard(cityId, cities[cityId]);
-  } else {
-    throw new Error("#city-dropdown is not a select element");
-  }
+  // Load initial city.
+  const cityId = cityToggleElement.value;
+  setUpAutoScorecard(map, cities, parkingLayer);
+  snapToCity(map, cities[cityId].layer);
+  setScorecard(cityId, cities[cityId]);
 };
 
 /**
@@ -277,22 +273,20 @@ const setUpParkingLotsLayer = async (
     },
   }).addTo(map);
 
+  if (window.location.href.indexOf("#lots-toggle") === -1) return parkingLayer;
+
   // If `#lots-toggle` is in the URL, we show buttons to toggle parking lots.
-  if (window.location.href.indexOf("#lots-toggle") !== -1) {
-    const toggle: HTMLAnchorElement | null =
-      document.querySelector("#lots-toggle");
-    if (toggle) {
-      toggle.style.display = "block";
-    }
-    document
-      .querySelector("#lots-toggle-off")
-      ?.addEventListener("click", () => {
-        parkingLayer.removeFrom(map);
-      });
-    document.querySelector("#lots-toggle-on")?.addEventListener("click", () => {
-      parkingLayer.addTo(map);
-    });
+  const toggle: HTMLAnchorElement | null =
+    document.querySelector("#lots-toggle");
+  if (toggle) {
+    toggle.style.display = "block";
   }
+  document.querySelector("#lots-toggle-off")?.addEventListener("click", () => {
+    parkingLayer.removeFrom(map);
+  });
+  document.querySelector("#lots-toggle-on")?.addEventListener("click", () => {
+    parkingLayer.addTo(map);
+  });
   return parkingLayer;
 };
 
diff --git a/src/js/share.ts b/src/js/share.ts
index c5e6e79..dca3b76 100644
--- a/src/js/share.ts
+++ b/src/js/share.ts
@@ -12,41 +12,33 @@ const copyToClipboard = async (value: string): Promise<void> => {
 };
 
 const switchIcons = (shareIcon: HTMLAnchorElement): void => {
-  const linkIcon: HTMLAnchorElement | null = shareIcon.querySelector(
-    "svg.share-link-icon"
-  );
-  const checkIcon: HTMLAnchorElement | null = shareIcon.querySelector(
-    "svg.share-check-icon"
-  );
-  if (linkIcon && checkIcon) {
-    linkIcon.style.display = "none";
-    checkIcon.style.display = "inline-block";
-    setTimeout(() => {
-      linkIcon.style.display = "inline-block";
-      checkIcon.style.display = "none";
-    }, 1000);
-  }
+  const linkIcon = shareIcon.querySelector("svg.share-link-icon");
+  const checkIcon = shareIcon.querySelector("svg.share-check-icon");
+  if (!(linkIcon instanceof SVGElement) || !(checkIcon instanceof SVGElement))
+    return;
+
+  linkIcon.style.display = "none";
+  checkIcon.style.display = "inline-block";
+  setTimeout(() => {
+    linkIcon.style.display = "inline-block";
+    checkIcon.style.display = "none";
+  }, 1000);
 };
 
 const setUpShareUrlClickListener = (cityId: CityId): void => {
   // We put the event listener on `map` because it is never erased, unlike the copy button
   // being recreated every time the score card changes. This is called "event delegation".
-  const mapElement: HTMLElement | null = document.querySelector("#map");
-  if (mapElement) {
-    mapElement.addEventListener("click", async (event: MouseEvent | null) => {
-      const copyButton = event?.target as Element;
-      if (copyButton) {
-        const targetElement: HTMLAnchorElement | null = copyButton.closest(
-          "div.url-copy-button > a"
-        );
-        if (targetElement) {
-          const shareUrl = determineShareUrl(window.location.href, cityId);
-          await copyToClipboard(shareUrl);
-          switchIcons(targetElement);
-        }
-      }
-    });
-  }
+  const mapElement = document.querySelector("#map");
+  if (!(mapElement instanceof Element)) return;
+  mapElement.addEventListener("click", async (event) => {
+    const copyButton = event.target;
+    if (!(copyButton instanceof Element)) return;
+    const targetElement = copyButton.closest("div.url-copy-button > a");
+    if (!(targetElement instanceof HTMLAnchorElement)) return;
+    const shareUrl = determineShareUrl(window.location.href, cityId);
+    await copyToClipboard(shareUrl);
+    switchIcons(targetElement);
+  });
 };
 
 export default setUpShareUrlClickListener;