typescript: Enable strictNullChecks.

Signed-off-by: Anders Kaseorg <anders@zulip.com>
2025-10-23 03:31:56 +00:00 · 2021-04-02 15:19:42 -07:00
parent 33c21d0153
commit 9a81ade1c8
13 changed files with 129 additions and 117 deletions
--- a/app/main/menu.ts
+++ b/app/main/menu.ts
@@ -292,7 +292,7 @@ function getHelpSubmenu(): Electron.MenuItemConstructorOptions[] {

 function getWindowSubmenu(
  tabs: TabData[],
-  activeTabIndex: number,
+  activeTabIndex?: number,
 ): Electron.MenuItemConstructorOptions[] {
  const initialSubmenu: Electron.MenuItemConstructorOptions[] = [
    {
@@ -342,7 +342,7 @@ function getWindowSubmenu(
          if (focusedWindow) {
            sendAction(
              "switch-server-tab",
-              getNextServer(tabs, activeTabIndex),
+              getNextServer(tabs, activeTabIndex!),
            );
          }
        },
@@ -355,7 +355,7 @@ function getWindowSubmenu(
          if (focusedWindow) {
            sendAction(
              "switch-server-tab",
-              getPreviousServer(tabs, activeTabIndex),
+              getPreviousServer(tabs, activeTabIndex!),
            );
          }
        },
@@ -367,7 +367,7 @@ function getWindowSubmenu(
 }

 function getDarwinTpl(props: MenuProps): Electron.MenuItemConstructorOptions[] {
-  const {tabs, activeTabIndex, enableMenu} = props;
+  const {tabs, activeTabIndex, enableMenu = false} = props;

  return [
    {
@@ -533,7 +533,7 @@ function getDarwinTpl(props: MenuProps): Electron.MenuItemConstructorOptions[] {
 }

 function getOtherTpl(props: MenuProps): Electron.MenuItemConstructorOptions[] {
-  const {tabs, activeTabIndex, enableMenu} = props;
+  const {tabs, activeTabIndex, enableMenu = false} = props;
  return [
    {
      label: t.__("File"),
--- a/app/renderer/js/components/functional-tab.ts
+++ b/app/renderer/js/components/functional-tab.ts
@@ -6,7 +6,8 @@ import type {TabProps} from "./tab";
 import Tab from "./tab";

 export default class FunctionalTab extends Tab {
-  $closeButton: Element;
+  $el: Element;
+  $closeButton?: Element;

  constructor(props: TabProps) {
    super(props);
@@ -14,7 +15,7 @@ export default class FunctionalTab extends Tab {
    this.$el = generateNodeFromHTML(this.templateHTML());
    if (this.props.name !== "Settings") {
      this.props.$root.append(this.$el);
-      this.$closeButton = this.$el.querySelector(".server-tab-badge");
+      this.$closeButton = this.$el.querySelector(".server-tab-badge")!;
      this.registerListeners();
    }
  }
@@ -36,15 +37,15 @@ export default class FunctionalTab extends Tab {
    super.registerListeners();

    this.$el.addEventListener("mouseover", () => {
-      this.$closeButton.classList.add("active");
+      this.$closeButton?.classList.add("active");
    });

    this.$el.addEventListener("mouseout", () => {
-      this.$closeButton.classList.remove("active");
+      this.$closeButton?.classList.remove("active");
    });

-    this.$closeButton.addEventListener("click", (event: Event) => {
-      this.props.onDestroy();
+    this.$closeButton?.addEventListener("click", (event: Event) => {
+      this.props.onDestroy?.();
      event.stopPropagation();
    });
  }
--- a/app/renderer/js/components/handle-external-link.ts
+++ b/app/renderer/js/components/handle-external-link.ts
@@ -59,7 +59,7 @@ export default function handleExternalLink(
            body: "Download failed",
          });
        } else {
-          this.$el.downloadURL(url.href);
+          this.$el!.downloadURL(url.href);
        }
      }

--- a/app/renderer/js/components/server-tab.ts
+++ b/app/renderer/js/components/server-tab.ts
@@ -9,6 +9,7 @@ import type {TabProps} from "./tab";
 import Tab from "./tab";

 export default class ServerTab extends Tab {
+  $el: Element;
  $badge: Element;

  constructor(props: TabProps) {
@@ -17,7 +18,7 @@ export default class ServerTab extends Tab {
    this.$el = generateNodeFromHTML(this.templateHTML());
    this.props.$root.append(this.$el);
    this.registerListeners();
-    this.$badge = this.$el.querySelector(".server-tab-badge");
+    this.$badge = this.$el.querySelector(".server-tab-badge")!;
  }

  templateHTML(): HTML {
--- a/app/renderer/js/components/tab.ts
+++ b/app/renderer/js/components/tab.ts
@@ -15,10 +15,11 @@ export interface TabProps {
  onDestroy?: () => void;
 }

-export default class Tab {
+export default abstract class Tab {
  props: TabProps;
  webview: WebView;
-  $el: Element;
+  abstract $el: Element;
+
  constructor(props: TabProps) {
    this.props = props;
    this.webview = this.props.webview;
@@ -26,8 +27,14 @@ export default class Tab {

  registerListeners(): void {
    this.$el.addEventListener("click", this.props.onClick);
-    this.$el.addEventListener("mouseover", this.props.onHover);
-    this.$el.addEventListener("mouseout", this.props.onHoverOut);
+
+    if (this.props.onHover !== undefined) {
+      this.$el.addEventListener("mouseover", this.props.onHover);
+    }
+
+    if (this.props.onHoverOut !== undefined) {
+      this.$el.addEventListener("mouseout", this.props.onHoverOut);
+    }
  }

  showNetworkError(): void {
@@ -46,6 +53,6 @@ export default class Tab {

  destroy(): void {
    this.$el.remove();
-    this.webview.$el.remove();
+    this.webview.$el!.remove();
  }
 }
--- a/app/renderer/js/components/webview.ts
+++ b/app/renderer/js/components/webview.ts
@@ -35,9 +35,9 @@ export default class WebView {
  zoomFactor: number;
  badgeCount: number;
  loading: boolean;
-  customCSS: string;
+  customCSS: string | null;
  $webviewsContainer: DOMTokenList;
-  $el: Electron.WebviewTag;
+  $el?: Electron.WebviewTag;
  domReady?: Promise<void>;

  constructor(props: WebViewProps) {
@@ -48,7 +48,7 @@ export default class WebView {
    this.customCSS = ConfigUtil.getConfigItem("customCSS");
    this.$webviewsContainer = document.querySelector(
      "#webviews-container",
-    ).classList;
+    )!.classList;
  }

  templateHTML(): HTML {
@@ -74,7 +74,7 @@ export default class WebView {
  init(): void {
    this.$el = generateNodeFromHTML(this.templateHTML()) as Electron.WebviewTag;
    this.domReady = new Promise((resolve) => {
-      this.$el.addEventListener(
+      this.$el!.addEventListener(
        "dom-ready",
        () => {
          resolve();
@@ -88,23 +88,23 @@ export default class WebView {
  }

  registerListeners(): void {
-    this.$el.addEventListener("new-window", (event) => {
+    this.$el!.addEventListener("new-window", (event) => {
      handleExternalLink.call(this, event);
    });

    if (shouldSilentWebview) {
-      this.$el.addEventListener("dom-ready", () => {
-        this.$el.setAudioMuted(true);
+      this.$el!.addEventListener("dom-ready", () => {
+        this.$el!.setAudioMuted(true);
      });
    }

-    this.$el.addEventListener("page-title-updated", (event) => {
+    this.$el!.addEventListener("page-title-updated", (event) => {
      const {title} = event;
      this.badgeCount = this.getBadgeCount(title);
      this.props.onTitleChange();
    });

-    this.$el.addEventListener("did-navigate-in-page", (event) => {
+    this.$el!.addEventListener("did-navigate-in-page", (event) => {
      const isSettingPage = event.url.includes("renderer/preference.html");
      if (isSettingPage) {
        return;
@@ -113,11 +113,11 @@ export default class WebView {
      this.canGoBackButton();
    });

-    this.$el.addEventListener("did-navigate", () => {
+    this.$el!.addEventListener("did-navigate", () => {
      this.canGoBackButton();
    });

-    this.$el.addEventListener("page-favicon-updated", (event) => {
+    this.$el!.addEventListener("page-favicon-updated", (event) => {
      const {favicons} = event;

      // This returns a string of favicons URL. If there is a PM counts in unread messages then the URL would be like
@@ -135,16 +135,16 @@ export default class WebView {
      }
    });

-    this.$el.addEventListener("dom-ready", () => {
+    this.$el!.addEventListener("dom-ready", () => {
      const webContents = remote.webContents.fromId(
-        this.$el.getWebContentsId(),
+        this.$el!.getWebContentsId(),
      );
      webContents.addListener("context-menu", (event, menuParameters) => {
        contextMenu(webContents, event, menuParameters);
      });

      if (this.props.role === "server") {
-        this.$el.classList.add("onload");
+        this.$el!.classList.add("onload");
      }

      this.loading = false;
@@ -153,11 +153,11 @@ export default class WebView {

      // Refocus text boxes after reload
      // Remove when upstream issue https://github.com/electron/electron/issues/14474 is fixed
-      this.$el.blur();
-      this.$el.focus();
+      this.$el!.blur();
+      this.$el!.focus();
    });

-    this.$el.addEventListener("did-fail-load", (event) => {
+    this.$el!.addEventListener("did-fail-load", (event) => {
      const {errorDescription} = event;
      const hasConnectivityError = SystemUtil.connectivityERR.includes(
        errorDescription,
@@ -170,14 +170,14 @@ export default class WebView {
      }
    });

-    this.$el.addEventListener("did-start-loading", () => {
+    this.$el!.addEventListener("did-start-loading", () => {
      const isSettingPage = this.props.url.includes("renderer/preference.html");
      if (!isSettingPage) {
        this.props.switchLoading(true, this.props.url);
      }
    });

-    this.$el.addEventListener("did-stop-loading", () => {
+    this.$el!.addEventListener("did-stop-loading", () => {
      this.props.switchLoading(false, this.props.url);
    });
  }
@@ -189,7 +189,7 @@ export default class WebView {

  showNotificationSettings(): void {
    ipcRenderer.sendTo(
-      this.$el.getWebContentsId(),
+      this.$el!.getWebContentsId(),
      "show-notification-settings",
    );
  }
@@ -207,18 +207,18 @@ export default class WebView {
      this.$webviewsContainer.add("loaded");
    }

-    this.$el.classList.remove("disabled");
-    this.$el.classList.add("active");
+    this.$el!.classList.remove("disabled");
+    this.$el!.classList.add("active");
    setTimeout(() => {
      if (this.props.role === "server") {
-        this.$el.classList.remove("onload");
+        this.$el!.classList.remove("onload");
      }
    }, 1000);
    this.focus();
    this.props.onTitleChange();
    // Injecting preload css in webview to override some css rules
    (async () =>
-      this.$el.insertCSS(
+      this.$el!.insertCSS(
        fs.readFileSync(path.join(__dirname, "/../../css/preload.css"), "utf8"),
      ))();

@@ -235,15 +235,15 @@ export default class WebView {
      }

      (async () =>
-        this.$el.insertCSS(
-          fs.readFileSync(path.resolve(__dirname, this.customCSS), "utf8"),
+        this.$el!.insertCSS(
+          fs.readFileSync(path.resolve(__dirname, this.customCSS!), "utf8"),
        ))();
    }
  }

  focus(): void {
    // Focus Webview and it's contents when Window regain focus.
-    const webContents = remote.webContents.fromId(this.$el.getWebContentsId());
+    const webContents = remote.webContents.fromId(this.$el!.getWebContentsId());
    // HACK: webContents.isFocused() seems to be true even without the element
    // being in focus. So, we check against `document.activeElement`.
    if (webContents && this.$el !== document.activeElement) {
@@ -251,14 +251,14 @@ export default class WebView {
      // element to transfer focus correctly, in Electron v3.0.10
      // See https://github.com/electron/electron/issues/15718
      (document.activeElement as HTMLElement).blur();
-      this.$el.focus();
+      this.$el!.focus();
      webContents.focus();
    }
  }

  hide(): void {
-    this.$el.classList.add("disabled");
-    this.$el.classList.remove("active");
+    this.$el!.classList.add("disabled");
+    this.$el!.classList.remove("active");
  }

  load(): void {
@@ -271,34 +271,34 @@ export default class WebView {

  zoomIn(): void {
    this.zoomFactor += 0.1;
-    this.$el.setZoomFactor(this.zoomFactor);
+    this.$el!.setZoomFactor(this.zoomFactor);
  }

  zoomOut(): void {
    this.zoomFactor -= 0.1;
-    this.$el.setZoomFactor(this.zoomFactor);
+    this.$el!.setZoomFactor(this.zoomFactor);
  }

  zoomActualSize(): void {
    this.zoomFactor = 1;
-    this.$el.setZoomFactor(this.zoomFactor);
+    this.$el!.setZoomFactor(this.zoomFactor);
  }

  logOut(): void {
-    ipcRenderer.sendTo(this.$el.getWebContentsId(), "logout");
+    ipcRenderer.sendTo(this.$el!.getWebContentsId(), "logout");
  }

  showKeyboardShortcuts(): void {
-    ipcRenderer.sendTo(this.$el.getWebContentsId(), "show-keyboard-shortcuts");
+    ipcRenderer.sendTo(this.$el!.getWebContentsId(), "show-keyboard-shortcuts");
  }

  openDevTools(): void {
-    this.$el.openDevTools();
+    this.$el!.openDevTools();
  }

  back(): void {
-    if (this.$el.canGoBack()) {
-      this.$el.goBack();
+    if (this.$el!.canGoBack()) {
+      this.$el!.goBack();
      this.focus();
    }
  }
@@ -306,8 +306,8 @@ export default class WebView {
  canGoBackButton(): void {
    const $backButton = document.querySelector(
      "#actions-container #back-action",
-    );
-    if (this.$el.canGoBack()) {
+    )!;
+    if (this.$el!.canGoBack()) {
      $backButton.classList.remove("disable");
    } else {
      $backButton.classList.add("disable");
@@ -315,8 +315,8 @@ export default class WebView {
  }

  forward(): void {
-    if (this.$el.canGoForward()) {
-      this.$el.goForward();
+    if (this.$el!.canGoForward()) {
+      this.$el!.goForward();
    }
  }

@@ -326,7 +326,7 @@ export default class WebView {
    this.$webviewsContainer.remove("loaded");
    this.loading = true;
    this.props.switchLoading(true, this.props.url);
-    this.$el.reload();
+    this.$el!.reload();
  }

  forceLoad(): void {
@@ -335,6 +335,6 @@ export default class WebView {

  async send(channel: string, ...parameters: unknown[]): Promise<void> {
    await this.domReady;
-    await this.$el.send(channel, ...parameters);
+    await this.$el!.send(channel, ...parameters);
  }
 }
--- a/app/renderer/js/feedback.ts
+++ b/app/renderer/js/feedback.ts
@@ -9,8 +9,8 @@ const {app} = remote;
 customElements.define("send-feedback", SendFeedback);
 export const sendFeedback: SendFeedback = document.querySelector(
  "send-feedback",
-);
-export const feedbackHolder = sendFeedback.parentElement;
+)!;
+export const feedbackHolder = sendFeedback.parentElement!;

 // Make the button color match zulip app's theme
 sendFeedback.customStylesheet = "css/feedback.css";
--- a/app/renderer/js/main.ts
+++ b/app/renderer/js/main.ts
@@ -86,21 +86,25 @@ class ServerManagerView {
  tabIndex: number;
  presetOrgs: string[];
  constructor() {
-    this.$addServerButton = document.querySelector("#add-tab");
-    this.$tabsContainer = document.querySelector("#tabs-container");
+    this.$addServerButton = document.querySelector("#add-tab")!;
+    this.$tabsContainer = document.querySelector("#tabs-container")!;

-    const $actionsContainer = document.querySelector("#actions-container");
-    this.$reloadButton = $actionsContainer.querySelector("#reload-action");
-    this.$loadingIndicator = $actionsContainer.querySelector("#loading-action");
-    this.$settingsButton = $actionsContainer.querySelector("#settings-action");
-    this.$webviewsContainer = document.querySelector("#webviews-container");
-    this.$backButton = $actionsContainer.querySelector("#back-action");
-    this.$dndButton = $actionsContainer.querySelector("#dnd-action");
+    const $actionsContainer = document.querySelector("#actions-container")!;
+    this.$reloadButton = $actionsContainer.querySelector("#reload-action")!;
+    this.$loadingIndicator = $actionsContainer.querySelector(
+      "#loading-action",
+    )!;
+    this.$settingsButton = $actionsContainer.querySelector("#settings-action")!;
+    this.$webviewsContainer = document.querySelector("#webviews-container")!;
+    this.$backButton = $actionsContainer.querySelector("#back-action")!;
+    this.$dndButton = $actionsContainer.querySelector("#dnd-action")!;

-    this.$addServerTooltip = document.querySelector("#add-server-tooltip");
-    this.$reloadTooltip = $actionsContainer.querySelector("#reload-tooltip");
-    this.$loadingTooltip = $actionsContainer.querySelector("#loading-tooltip");
-    this.$settingsTooltip = $actionsContainer.querySelector("#setting-tooltip");
+    this.$addServerTooltip = document.querySelector("#add-server-tooltip")!;
+    this.$reloadTooltip = $actionsContainer.querySelector("#reload-tooltip")!;
+    this.$loadingTooltip = $actionsContainer.querySelector("#loading-tooltip")!;
+    this.$settingsTooltip = $actionsContainer.querySelector(
+      "#setting-tooltip",
+    )!;

    // TODO: This should have been querySelector but the problem is that
    // querySelector doesn't return elements not present in dom whereas somehow
@@ -110,12 +114,12 @@ class ServerManagerView {
    this.$serverIconTooltip = document.getElementsByClassName(
      "server-tooltip",
    ) as HTMLCollectionOf<HTMLElement>;
-    this.$backTooltip = $actionsContainer.querySelector("#back-tooltip");
-    this.$dndTooltip = $actionsContainer.querySelector("#dnd-tooltip");
+    this.$backTooltip = $actionsContainer.querySelector("#back-tooltip")!;
+    this.$dndTooltip = $actionsContainer.querySelector("#dnd-tooltip")!;

-    this.$sidebar = document.querySelector("#sidebar");
+    this.$sidebar = document.querySelector("#sidebar")!;

-    this.$fullscreenPopup = document.querySelector("#fullscreen-popup");
+    this.$fullscreenPopup = document.querySelector("#fullscreen-popup")!;
    this.$fullscreenEscapeKey = process.platform === "darwin" ? "^⌘F" : "F11";
    this.$fullscreenPopup.textContent = `Press ${this.$fullscreenEscapeKey} to exit full screen`;

@@ -486,12 +490,12 @@ class ServerManagerView {
    // error

    const $altIcon = document.createElement("div");
-    const $parent = $img.parentElement;
-    const $container = $parent.parentElement;
-    const webviewId = $container.dataset.tabId;
+    const $parent = $img.parentElement!;
+    const $container = $parent.parentElement!;
+    const webviewId = $container.dataset.tabId!;
    const $webview = document.querySelector(
      `webview[data-tab-id="${CSS.escape(webviewId)}"]`,
-    );
+    )!;
    const realmName = $webview.getAttribute("name");

    if (realmName === null) {
@@ -539,7 +543,7 @@ class ServerManagerView {
    // as that of its parent element.
    const {top} = this.$serverIconTooltip[
      index
-    ].parentElement.getBoundingClientRect();
+    ].parentElement!.getBoundingClientRect();
    this.$serverIconTooltip[index].style.top = `${top}px`;
  }

@@ -549,7 +553,7 @@ class ServerManagerView {

  openFunctionalTab(tabProps: FunctionalTabProps): void {
    if (this.functionalTabs.has(tabProps.name)) {
-      this.activateTab(this.functionalTabs.get(tabProps.name));
+      this.activateTab(this.functionalTabs.get(tabProps.name)!);
      return;
    }

@@ -563,20 +567,20 @@ class ServerManagerView {
        materialIcon: tabProps.materialIcon,
        name: tabProps.name,
        $root: this.$tabsContainer,
-        index: this.functionalTabs.get(tabProps.name),
+        index: this.functionalTabs.get(tabProps.name)!,
        tabIndex,
        onClick: this.activateTab.bind(
          this,
-          this.functionalTabs.get(tabProps.name),
+          this.functionalTabs.get(tabProps.name)!,
        ),
        onDestroy: this.destroyTab.bind(
          this,
          tabProps.name,
-          this.functionalTabs.get(tabProps.name),
+          this.functionalTabs.get(tabProps.name)!,
        ),
        webview: new WebView({
          $root: this.$webviewsContainer,
-          index: this.functionalTabs.get(tabProps.name),
+          index: this.functionalTabs.get(tabProps.name)!,
          tabIndex,
          url: tabProps.url,
          role: "function",
@@ -610,7 +614,7 @@ class ServerManagerView {
    // closed when the functional tab DOM is ready, handled in webview.js
    this.$webviewsContainer.classList.remove("loaded");

-    this.activateTab(this.functionalTabs.get(tabProps.name));
+    this.activateTab(this.functionalTabs.get(tabProps.name)!);
  }

  async openSettings(nav: NavItem = "General"): Promise<void> {
@@ -620,7 +624,7 @@ class ServerManagerView {
      url: `file://${rendererDirectory}/preference.html#${nav}`,
    });
    this.$settingsButton.classList.add("active");
-    await this.tabs[this.functionalTabs.get("Settings")].webview.send(
+    await this.tabs[this.functionalTabs.get("Settings")!].webview.send(
      "switch-settings-nav",
      nav,
    );
@@ -798,19 +802,19 @@ class ServerManagerView {
  toggleDNDButton(alert: boolean): void {
    this.$dndTooltip.textContent =
      (alert ? "Disable" : "Enable") + " Do Not Disturb";
-    this.$dndButton.querySelector("i").textContent = alert
+    this.$dndButton.querySelector("i")!.textContent = alert
      ? "notifications_off"
      : "notifications";
  }

  isLoggedIn(tabIndex: number): boolean {
-    const url = this.tabs[tabIndex].webview.$el.src;
+    const url = this.tabs[tabIndex].webview.$el!.src;
    return !(url.endsWith("/login/") || this.tabs[tabIndex].webview.loading);
  }

  getActiveWebview(): Electron.WebviewTag {
    const selector = "webview:not(.disabled)";
-    const webview: Electron.WebviewTag = document.querySelector(selector);
+    const webview: Electron.WebviewTag = document.querySelector(selector)!;
    return webview;
  }

@@ -954,7 +958,7 @@ class ServerManagerView {
            : this.tabs.some(
                ({webview}) =>
                  !webview.loading &&
-                  webview.$el.getWebContentsId() === webContentsId &&
+                  webview.$el!.getWebContentsId() === webContentsId &&
                  webview.props.hasPermission?.(origin, permission),
              );
        console.log(
@@ -1132,10 +1136,10 @@ class ServerManagerView {
        );
        for (const webview of webviews) {
          const currentId = webview.getWebContentsId();
-          const tabId = webview.getAttribute("data-tab-id");
+          const tabId = webview.getAttribute("data-tab-id")!;
          const concurrentTab: HTMLButtonElement = document.querySelector(
            `div[data-tab-id="${CSS.escape(tabId)}"]`,
-          );
+          )!;
          if (currentId === webviewId) {
            concurrentTab.click();
          }
@@ -1152,7 +1156,7 @@ class ServerManagerView {
          canvas.height = 128;
          canvas.width = 128;
          canvas.style.letterSpacing = "-5px";
-          const ctx = canvas.getContext("2d");
+          const ctx = canvas.getContext("2d")!;
          ctx.fillStyle = "#f42020";
          ctx.beginPath();
          ctx.ellipse(64, 64, 64, 64, 0, 0, 2 * Math.PI);
--- a/app/renderer/js/pages/preference/nav.ts
+++ b/app/renderer/js/pages/preference/nav.ts
@@ -53,7 +53,7 @@ export default class PreferenceNav {

  registerListeners(): void {
    for (const navItem of this.navItems) {
-      const $item = document.querySelector(`#nav-${CSS.escape(navItem)}`);
+      const $item = document.querySelector(`#nav-${CSS.escape(navItem)}`)!;
      $item.addEventListener("click", () => {
        this.props.onItemSelected(navItem);
      });
@@ -71,12 +71,12 @@ export default class PreferenceNav {
  }

  activate(navItem: NavItem): void {
-    const $item = document.querySelector(`#nav-${CSS.escape(navItem)}`);
+    const $item = document.querySelector(`#nav-${CSS.escape(navItem)}`)!;
    $item.classList.add("active");
  }

  deactivate(navItem: NavItem): void {
-    const $item = document.querySelector(`#nav-${CSS.escape(navItem)}`);
+    const $item = document.querySelector(`#nav-${CSS.escape(navItem)}`)!;
    $item.classList.remove("active");
  }
 }
--- a/app/renderer/js/preload.ts
+++ b/app/renderer/js/preload.ts
@@ -12,7 +12,7 @@ ipcRenderer.on("logout", () => {
  }

  // Create the menu for the below
-  const dropdown: HTMLElement = document.querySelector(".dropdown-toggle");
+  const dropdown: HTMLElement = document.querySelector(".dropdown-toggle")!;
  dropdown.click();

  const nodes: NodeListOf<HTMLElement> = document.querySelectorAll(
@@ -29,13 +29,13 @@ ipcRenderer.on("show-keyboard-shortcuts", () => {
  // Create the menu for the below
  const node: HTMLElement = document.querySelector(
    "a[data-overlay-trigger=keyboard-shortcuts]",
-  );
+  )!;
  // Additional check
-  if (node.textContent.trim().toLowerCase() === "keyboard shortcuts (?)") {
+  if (node.textContent!.trim().toLowerCase() === "keyboard shortcuts (?)") {
    node.click();
  } else {
    // Atleast click the dropdown
-    const dropdown: HTMLElement = document.querySelector(".dropdown-toggle");
+    const dropdown: HTMLElement = document.querySelector(".dropdown-toggle")!;
    dropdown.click();
  }
 });
@@ -46,7 +46,7 @@ ipcRenderer.on("show-notification-settings", () => {
  }

  // Create the menu for the below
-  const dropdown: HTMLElement = document.querySelector(".dropdown-toggle");
+  const dropdown: HTMLElement = document.querySelector(".dropdown-toggle")!;
  dropdown.click();

  const nodes: NodeListOf<HTMLElement> = document.querySelectorAll(
@@ -69,8 +69,8 @@ window.addEventListener("load", (event: any): void => {
    return;
  }

-  const $reconnectButton = document.querySelector("#reconnect");
-  const $settingsButton = document.querySelector("#settings");
+  const $reconnectButton = document.querySelector("#reconnect")!;
+  const $settingsButton = document.querySelector("#settings")!;
  NetworkError.init($reconnectButton, $settingsButton);
 });

--- a/app/renderer/js/tray.ts
+++ b/app/renderer/js/tray.ts
@@ -6,7 +6,7 @@ import * as ConfigUtil from "../../common/config-util";

 const {Tray, Menu, nativeImage, BrowserWindow} = remote;

-let tray: Electron.Tray;
+let tray: Electron.Tray | null = null;

 const ICON_DIR = "../../resources/tray";

@@ -69,7 +69,7 @@ const renderCanvas = function (arg: number): HTMLCanvasElement {
  const canvas = document.createElement("canvas");
  canvas.width = SIZE;
  canvas.height = SIZE;
-  const ctx = canvas.getContext("2d");
+  const ctx = canvas.getContext("2d")!;

  // Circle
  // If (!config.thick || config.thick && HAS_COUNT) {
@@ -210,15 +210,15 @@ function toggleTray(): void {
    createTray();
    if (process.platform === "linux" || process.platform === "win32") {
      const image = renderNativeImage(unread);
-      tray.setImage(image);
-      tray.setToolTip(`${unread} unread messages`);
+      tray!.setImage(image);
+      tray!.setToolTip(`${unread} unread messages`);
    }

    ConfigUtil.setConfigItem("trayIcon", true);
  }

  const selector = "webview:not([class*=disabled])";
-  const webview: WebviewTag = document.querySelector(selector);
+  const webview: WebviewTag = document.querySelector(selector)!;
  const webContents = remote.webContents.fromId(webview.getWebContentsId());
  webContents.send("toggletray", state);
 }
--- a/app/renderer/js/utils/domain-util.ts
+++ b/app/renderer/js/utils/domain-util.ts
@@ -17,7 +17,7 @@ const logger = new Logger({

 const defaultIconUrl = "../renderer/img/icon.png";

-let db: JsonDB;
+let db!: JsonDB;

 reloadDB();
 // Migrate from old schema
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -10,7 +10,6 @@
    /* Strict type-checking */
    "strict": true,
    "noImplicitAny": true,
-    "strictNullChecks": false,
    "noImplicitThis": true,
    "alwaysStrict": true,