diff --git a/src/addon-manager.ts b/src/addon-manager.ts
index 8b210ed63..aae825c15 100644
--- a/src/addon-manager.ts
+++ b/src/addon-manager.ts
@@ -78,7 +78,7 @@ export class AddonManager extends EventEmitter {
 
   private updateTimeout: NodeJS.Timeout | null = null;
 
-  private updateInterval: number | null = null;
+  private updateInterval: NodeJS.Timeout | null = null;
 
   private pairingTimeout: NodeJS.Timeout | null = null;
 
diff --git a/src/controllers/login_controller.ts b/src/controllers/login_controller.ts
index c2960fca6..ff4b04af0 100644
--- a/src/controllers/login_controller.ts
+++ b/src/controllers/login_controller.ts
@@ -92,7 +92,9 @@ function build(): express.Router {
 
     // Issue a new JWT for this user.
     const jwt = await JSONWebToken.issueToken(user.getId()!);
-    limiter.resetKey(request.ip);
+    if (request.ip) {
+      limiter.resetKey(request.ip);
+    }
     response.status(200).json({ jwt });
   });
 
diff --git a/src/log-timestamps.ts b/src/log-timestamps.ts
index 5377ab51f..dcba0a7f3 100644
--- a/src/log-timestamps.ts
+++ b/src/log-timestamps.ts
@@ -45,7 +45,7 @@ const logger = winston.createLogger({
             error: 'red',
           },
         }),
-        winston.format.printf((info) => info.message)
+        winston.format.printf((info) => String(info.message))
       ),
     }),
     new DailyRotateFile({
@@ -59,7 +59,7 @@ const logger = winston.createLogger({
       format: winston.format.combine(
         timestampFormat,
         new CustomFormatter(),
-        winston.format.printf((info) => info.message)
+        winston.format.printf((info) => String(info.message))
       ),
     }),
   ],
diff --git a/src/platforms/linux-raspbian.ts b/src/platforms/linux-raspbian.ts
index c2b28c163..d0ac8e495 100644
--- a/src/platforms/linux-raspbian.ts
+++ b/src/platforms/linux-raspbian.ts
@@ -158,7 +158,7 @@ class LinuxRaspbianPlatform extends BasePlatform {
       mgmt = '';
     const options: Record<string, unknown> = {};
 
-    let proc = child_process.spawnSync('systemctl', ['is-active', 'hostapd.service']);
+    const proc = child_process.spawnSync('systemctl', ['is-active', 'hostapd.service']);
     if (proc.status === 0) {
       mode = 'ap';
       enabled = true;
@@ -212,13 +212,15 @@ class LinuxRaspbianPlatform extends BasePlatform {
       }
     } else {
       mode = 'sta';
-      proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'status'], { encoding: 'utf8' });
+      const startProc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'status'], {
+        encoding: 'utf8',
+      });
 
       if (proc.status !== 0) {
         return { enabled, mode, options };
       }
 
-      for (const line of proc.stdout.split('\n')) {
+      for (const line of startProc.stdout.split('\n')) {
         const [key, value] = line.split('=', 2);
         switch (key) {
           case 'wpa_state':
@@ -248,7 +250,7 @@ class LinuxRaspbianPlatform extends BasePlatform {
         }
       }
 
-      proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'list_networks'], {
+      const listProc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'list_networks'], {
         encoding: 'utf8',
       });
       if (proc.status !== 0) {
@@ -256,7 +258,7 @@ class LinuxRaspbianPlatform extends BasePlatform {
       }
 
       options.networks = [];
-      for (const line of proc.stdout.trim().split('\n')) {
+      for (const line of listProc.stdout.trim().split('\n')) {
         if (line.startsWith('network')) {
           continue;
         }
@@ -299,19 +301,24 @@ class LinuxRaspbianPlatform extends BasePlatform {
     }
 
     // First, remove existing networks
-    let proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'list_networks'], {
+    const listProc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'list_networks'], {
       encoding: 'utf8',
     });
-    if (proc.status === 0) {
-      const networks = proc.stdout
+    if (listProc.status === 0) {
+      const networks = listProc.stdout
         .split('\n')
         .filter((l) => !l.startsWith('network'))
         .map((l) => l.split(' ')[0])
         .reverse();
 
       for (const id of networks) {
-        proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'remove_network', id]);
-        if (proc.status !== 0) {
+        const removeNetworkProc = child_process.spawnSync('wpa_cli', [
+          '-i',
+          'wlan0',
+          'remove_network',
+          id,
+        ]);
+        if (removeNetworkProc.status !== 0) {
           console.log('Failed to remove network with id:', id);
         }
       }
@@ -319,54 +326,58 @@ class LinuxRaspbianPlatform extends BasePlatform {
 
     // Then, stop hostapd. It will either need to be off or reconfigured, so
     // this is valid in both modes.
-    proc = child_process.spawnSync('sudo', ['systemctl', 'stop', 'hostapd.service']);
-    if (proc.status !== 0) {
+    const stopProc = child_process.spawnSync('sudo', ['systemctl', 'stop', 'hostapd.service']);
+    if (stopProc.status !== 0) {
       return false;
     }
 
     if (!enabled) {
-      proc = child_process.spawnSync('sudo', ['systemctl', 'disable', 'hostapd.service']);
-      return proc.status === 0;
+      const disableProc = child_process.spawnSync('sudo', [
+        'systemctl',
+        'disable',
+        'hostapd.service',
+      ]);
+      return disableProc.status === 0;
     }
 
     // Make sure Wi-Fi isn't blocked by rfkill
     child_process.spawnSync('sudo', ['rfkill', 'unblock', 'wifi']);
 
     // Now, set the IP address back to a sane state
-    proc = child_process.spawnSync('sudo', ['ifconfig', 'wlan0', '0.0.0.0']);
-    if (proc.status !== 0) {
+    const configProc = child_process.spawnSync('sudo', ['ifconfig', 'wlan0', '0.0.0.0']);
+    if (configProc.status !== 0) {
       return false;
     }
 
     if (mode === 'sta') {
-      proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'add_network'], {
+      const addProc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'add_network'], {
         encoding: 'utf8',
       });
-      if (proc.status !== 0) {
+      if (addProc.status !== 0) {
         return false;
       }
 
-      const id = proc.stdout.trim();
+      const id = addProc.stdout.trim();
 
       options.ssid = (<string>options.ssid).replace('"', '\\"');
-      proc = child_process.spawnSync(
+      let setProc = child_process.spawnSync(
         'wpa_cli',
         // the ssid argument MUST be quoted
         ['-i', 'wlan0', 'set_network', id, 'ssid', `"${options.ssid}"`]
       );
-      if (proc.status !== 0) {
+      if (setProc.status !== 0) {
         return false;
       }
 
       if (options.key) {
         options.key = (<string>options.key).replace('"', '\\"');
-        proc = child_process.spawnSync(
+        setProc = child_process.spawnSync(
           'wpa_cli',
           // the psk argument MUST be quoted
           ['-i', 'wlan0', 'set_network', id, 'psk', `"${options.key}"`]
         );
       } else {
-        proc = child_process.spawnSync('wpa_cli', [
+        setProc = child_process.spawnSync('wpa_cli', [
           '-i',
           'wlan0',
           'set_network',
@@ -376,22 +387,26 @@ class LinuxRaspbianPlatform extends BasePlatform {
         ]);
       }
 
-      if (proc.status !== 0) {
+      if (setProc.status !== 0) {
         return false;
       }
 
-      proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'enable_network', id]);
-      if (proc.status !== 0) {
+      const enableProc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'enable_network', id]);
+      if (enableProc.status !== 0) {
         return false;
       }
 
-      proc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'save_config']);
-      if (proc.status !== 0) {
+      const saveProc = child_process.spawnSync('wpa_cli', ['-i', 'wlan0', 'save_config']);
+      if (saveProc.status !== 0) {
         return false;
       }
 
-      proc = child_process.spawnSync('sudo', ['systemctl', 'disable', 'hostapd.service']);
-      if (proc.status !== 0) {
+      const disableProc = child_process.spawnSync('sudo', [
+        'systemctl',
+        'disable',
+        'hostapd.service',
+      ]);
+      if (disableProc.status !== 0) {
         return false;
       }
     } else {
@@ -409,30 +424,38 @@ class LinuxRaspbianPlatform extends BasePlatform {
 
       fs.writeFileSync('/tmp/hostapd.conf', config);
 
-      proc = child_process.spawnSync('sudo', [
+      const mvProc = child_process.spawnSync('sudo', [
         'mv',
         '/tmp/hostapd.conf',
         '/etc/hostapd/hostapd.conf',
       ]);
 
-      if (proc.status !== 0) {
+      if (mvProc.status !== 0) {
         return false;
       }
 
-      proc = child_process.spawnSync('sudo', ['systemctl', 'start', 'hostapd.service']);
-      if (proc.status !== 0) {
+      const startProc = child_process.spawnSync('sudo', ['systemctl', 'start', 'hostapd.service']);
+      if (startProc.status !== 0) {
         return false;
       }
 
-      proc = child_process.spawnSync('sudo', ['systemctl', 'enable', 'hostapd.service']);
-      if (proc.status !== 0) {
+      const enableProc = child_process.spawnSync('sudo', [
+        'systemctl',
+        'enable',
+        'hostapd.service',
+      ]);
+      if (enableProc.status !== 0) {
         return false;
       }
     }
 
     if (options.ipaddr) {
-      proc = child_process.spawnSync('sudo', ['ifconfig', 'wlan0', <string>options.ipaddr]);
-      if (proc.status !== 0) {
+      const configProc = child_process.spawnSync('sudo', [
+        'ifconfig',
+        'wlan0',
+        <string>options.ipaddr,
+      ]);
+      if (configProc.status !== 0) {
         return false;
       }
 
diff --git a/src/plugin/plugin.ts b/src/plugin/plugin.ts
index 4b9e17311..5c3c9e388 100644
--- a/src/plugin/plugin.ts
+++ b/src/plugin/plugin.ts
@@ -145,7 +145,7 @@ export default class Plugin {
 
   asDict(): Record<string, unknown> {
     let pid: string | number = 'not running';
-    if (this.process.p) {
+    if (this.process.p && typeof this.process.p.pid != 'undefined') {
       pid = this.process.p.pid;
     }
     return {
diff --git a/src/test/common.ts b/src/test/common.ts
index 76f25931b..94139f011 100644
--- a/src/test/common.ts
+++ b/src/test/common.ts
@@ -28,7 +28,7 @@ interface TestGlobals {
 }
 
 export const chai = _chai;
-(<NodeJS.Global & typeof globalThis & TestGlobals>global).chai = chai;
+(<typeof global & typeof globalThis & TestGlobals>global).chai = chai;
 
 expect.extend({
   assert(value, message = 'expected condition to be truthy') {
@@ -41,7 +41,7 @@ expect.extend({
 });
 
 import { servers, serverStartup } from '../app';
-(<NodeJS.Global & typeof globalThis & TestGlobals>global).server = servers.https!;
+(<typeof global & typeof globalThis & TestGlobals>global).server = servers.https!;
 
 import addonManager from '../addon-manager';
 
@@ -50,7 +50,7 @@ export function mockAdapter(): MockAdapter {
   expect(adapter).not.toBeUndefined();
   return <MockAdapter>(<unknown>adapter!);
 }
-(<NodeJS.Global & typeof globalThis & TestGlobals>global).mockAdapter = mockAdapter;
+(<typeof global & typeof globalThis & TestGlobals>global).mockAdapter = mockAdapter;
 
 function removeTestManifest(): void {
   const testManifestJsonFilename = path.join(
diff --git a/src/test/jsdom-common.ts b/src/test/jsdom-common.ts
index 26a1288e1..0a05781b0 100644
--- a/src/test/jsdom-common.ts
+++ b/src/test/jsdom-common.ts
@@ -24,11 +24,11 @@ interface TestGlobals {
 }
 
 beforeEach(() => {
-  (<NodeJS.Global & typeof globalThis & TestGlobals>global).sandbox = sinon.createSandbox();
+  (<typeof global & typeof globalThis & TestGlobals>global).sandbox = sinon.createSandbox();
 });
 
 afterEach(() => {
-  (<NodeJS.Global & typeof globalThis & TestGlobals>global).sandbox.restore();
+  (<typeof global & typeof globalThis & TestGlobals>global).sandbox.restore();
   // Clean up any nodes added to the DOM
   document.body.innerHTML = '';
 });
diff --git a/src/test/schema-form/form-test.ts b/src/test/schema-form/form-test.ts
index 0330d30d3..300204abb 100644
--- a/src/test/schema-form/form-test.ts
+++ b/src/test/schema-form/form-test.ts
@@ -359,7 +359,7 @@ describe('Form', () => {
           foo: { type: 'string' },
         },
       };
-      const onSubmit = (<NodeJS.Global & typeof globalThis & TestGlobals>global).sandbox.stub();
+      const onSubmit = (<typeof global & typeof globalThis & TestGlobals>global).sandbox.stub();
 
       const { node } = createSchemaForm({
         schema,
diff --git a/src/test/websocket-util.ts b/src/test/websocket-util.ts
index ff3c89123..bbec0d18d 100644
--- a/src/test/websocket-util.ts
+++ b/src/test/websocket-util.ts
@@ -77,12 +77,15 @@ export async function webSocketRead(
  * @param {Object|string} message
  */
 export async function webSocketSend(ws: WebSocket, message: unknown): Promise<void> {
-  if (typeof message !== 'string') {
-    message = JSON.stringify(message);
+  let messageString: string;
+  if (typeof message == 'string') {
+    messageString = message;
+  } else {
+    messageString = JSON.stringify(message);
   }
 
   await new Promise<void>((resolve) => {
-    ws.send(message, () => {
+    ws.send(messageString, () => {
       resolve();
     });
   });
diff --git a/static/js/schema-form/schema-utils.ts b/static/js/schema-form/schema-utils.ts
index 34525c8df..e9857ac51 100644
--- a/static/js/schema-form/schema-utils.ts
+++ b/static/js/schema-form/schema-utils.ts
@@ -121,7 +121,7 @@ export function withDependentSchema(
   schema = mergeSchemas(schema, dependentSchema);
   return typeof oneOf === 'undefined'
     ? schema
-    : withExactlyOneSubschema(schema, definitions, formData, dependencyKey, <unknown[]>oneOf);
+    : withExactlyOneSubschema(schema, definitions, formData, dependencyKey, <JsonSchema[]>oneOf);
 }
 
 export function withExactlyOneSubschema(
@@ -129,7 +129,7 @@ export function withExactlyOneSubschema(
   definitions: Record<string, unknown>,
   formData: Record<string, unknown>,
   dependencyKey: string,
-  oneOf: unknown[]
+  oneOf: JsonSchema[]
 ): Record<string, unknown> {
   if (!Array.isArray(oneOf)) {
     throw new Error(`invalid oneOf: it is some ${typeof oneOf} instead of an array`);
@@ -432,3 +432,11 @@ export function getOptionsList(schema: Record<string, unknown>): Record<string,
     });
   }
 }
+
+interface JsonSchema {
+  properties: Record<string, PropertySchema>;
+}
+
+interface PropertySchema {
+  type: string;
+}