refactor: prefer value guards for indexed access

thymikee · thymikee · commit c8c7e7d61483 · 2026-05-28T10:39:46.000+02:00
diff --git a/src/commands/cli-grammar/interactions.ts b/src/commands/cli-grammar/interactions.ts
@@ -140,15 +140,15 @@ function readLongPressTargetFromPositionals(positionals: string[]): LongPressOpt
 }
 
 export function readFillTargetFromPositionals(positionals: string[]): DecodedFillTarget {
-  if (positionals[0]?.startsWith('@')) {
+  const firstPositional = positionals[0];
+  if (firstPositional?.startsWith('@')) {
     const text =
       positionals.length >= 3 ? positionals.slice(2).join(' ') : positionals.slice(1).join(' ');
-    const maybeLabel = positionals[1];
     return {
       kind: 'ref',
       target: {
-        ref: positionals[0]!,
-        label: positionals.length >= 3 ? optionalTrimmedText([maybeLabel!]) : undefined,
+        ref: firstPositional,
+        label: positionals.length >= 3 ? optionalTrimmedText(positionals.slice(1, 2)) : undefined,
       },
       text,
     };
diff --git a/src/commands/interaction-targeting.ts b/src/commands/interaction-targeting.ts
@@ -80,7 +80,9 @@ function findPreferredActionableDescendant(
     if (sameRectChildren.length !== 1) {
       break;
     }
-    current = sameRectChildren[0]!;
+    const child = sameRectChildren[0];
+    if (child === undefined) break;
+    current = child;
   }
 
   return current === node ? null : current;
diff --git a/src/daemon-client.ts b/src/daemon-client.ts
@@ -265,15 +265,12 @@ async function prepareRemoteRequest(
       clientArtifactPaths,
     });
 
-  if (
-    !isRemoteDaemon(info) ||
-    (req.command !== 'install' && req.command !== 'reinstall') ||
-    positionals.length < 2
-  ) {
+  if (!isRemoteDaemon(info) || (req.command !== 'install' && req.command !== 'reinstall')) {
     return baseResult();
   }
 
-  const rawPath = positionals[1]!;
+  const rawPath = positionals[1];
+  if (rawPath === undefined) return baseResult();
   if (rawPath.startsWith('remote:')) {
     positionals[1] = rawPath.slice('remote:'.length);
     return createPreparedRemoteRequest({ positionals, flags, clientArtifactPaths });
@@ -959,7 +956,11 @@ function resolveDaemonLaunchSpec(): DaemonLaunchSpec {
     path.join(root, 'dist', 'src', 'internal', 'daemon.js'),
     path.join(root, 'dist', 'src', 'daemon.js'),
   ];
-  const distPath = distPaths.find((candidate) => fs.existsSync(candidate)) ?? distPaths[0]!;
+  const defaultDistPath = distPaths[0];
+  if (defaultDistPath === undefined) {
+    throw new AppError('COMMAND_FAILED', 'Daemon dist path list is empty');
+  }
+  const distPath = distPaths.find((candidate) => fs.existsSync(candidate)) ?? defaultDistPath;
   const srcPath = path.join(root, 'src', 'daemon.ts');
 
   const hasDist = distPaths.some((candidate) => fs.existsSync(candidate));
diff --git a/src/daemon/artifact-archive.ts b/src/daemon/artifact-archive.ts
@@ -92,7 +92,8 @@ function resolveArchiveRootName(entries: string[], platform: 'ios' | 'android'):
   const rootEntries = [...roots];
   if (platform === 'ios') {
     const appRoots = rootEntries.filter((entry) => entry.toLowerCase().endsWith('.app'));
-    if (appRoots.length === 1) return appRoots[0]!;
+    const appRoot = appRoots[0];
+    if (appRoot !== undefined && appRoots.length === 1) return appRoot;
     if (appRoots.length === 0) {
       throw new AppError(
         'INVALID_ARGS',
@@ -104,7 +105,8 @@ function resolveArchiveRootName(entries: string[], platform: 'ios' | 'android'):
       `iOS app bundle archives must contain exactly one top-level .app directory, found: ${appRoots.join(', ')}`,
     );
   }
-  if (rootEntries.length === 1) return rootEntries[0]!;
+  const rootEntry = rootEntries[0];
+  if (rootEntry !== undefined && rootEntries.length === 1) return rootEntry;
   throw new AppError(
     'INVALID_ARGS',
     `Archive must contain a single top-level bundle, found: ${rootEntries.join(', ')}`,
diff --git a/src/daemon/screenshot-overlay-rects.ts b/src/daemon/screenshot-overlay-rects.ts
@@ -18,7 +18,10 @@ export function rectContains(container: Rect, nested: Rect): boolean {
 }
 
 export function unionRects(rects: Rect[]): Rect {
-  const firstRect = rects[0]!;
+  const firstRect = rects[0];
+  if (firstRect === undefined) {
+    throw new Error('unionRects requires at least one rect');
+  }
   let minX = firstRect.x;
   let minY = firstRect.y;
   let maxRight = firstRect.x + firstRect.width;
diff --git a/src/daemon/selectors-parse.ts b/src/daemon/selectors-parse.ts
@@ -103,11 +103,13 @@ export function splitSelectorFromArgs(
     }
   }
   if (boundaries.length === 0) return null;
-  const lastBoundary = boundaries[boundaries.length - 1]!;
+  const lastBoundary = boundaries.at(-1);
+  if (lastBoundary === undefined) return null;
   let boundary = lastBoundary;
   if (preferTrailingValue) {
     for (let i = boundaries.length - 1; i >= 0; i -= 1) {
-      const candidateBoundary = boundaries[i]!;
+      const candidateBoundary = boundaries[i];
+      if (candidateBoundary === undefined) continue;
       if (candidateBoundary < args.length) {
         boundary = candidateBoundary;
         break;
diff --git a/src/daemon/session-routing.ts b/src/daemon/session-routing.ts
@@ -12,7 +12,8 @@ export function resolveEffectiveSessionName(
   if (sessionStore.has(requested)) return requested;
 
   const sessions = sessionStore.toArray();
-  if (sessions.length === 1) return sessions[0]!.name;
+  const session = sessions[0];
+  if (session !== undefined && sessions.length === 1) return session.name;
   return requested;
 }
 
diff --git a/src/platforms/android/app-lifecycle.ts b/src/platforms/android/app-lifecycle.ts
@@ -77,10 +77,11 @@ export async function resolveAndroidApp(
   const matches = packages.filter((pkg: string) =>
     pkg.toLowerCase().includes(trimmed.toLowerCase()),
   );
-  if (matches.length === 1) {
+  const match = matches[0];
+  if (match !== undefined && matches.length === 1) {
     return androidAppResolutionCache.set(cacheScope, trimmed, {
       type: 'package',
-      value: matches[0]!,
+      value: match,
     });
   }
 
@@ -586,9 +587,11 @@ export function parseAndroidLaunchComponent(stdout: string): string | null {
     .map((line: string) => line.trim())
     .filter(Boolean);
   for (let index = lines.length - 1; index >= 0; index -= 1) {
-    const line = lines[index]!;
+    const line = lines[index];
+    if (line === undefined) continue;
     if (!line.includes('/')) continue;
-    return line.split(/\s+/)[0]!;
+    const component = line.split(/\s+/)[0];
+    if (component !== undefined) return component;
   }
   return null;
 }
diff --git a/src/platforms/android/app-parsers.ts b/src/platforms/android/app-parsers.ts
@@ -86,7 +86,9 @@ function parseAndroidBlockingDialogFromSegment(
   const respondingMatch = ANDROID_RESPONDING_TITLE_PATTERN.exec(windowText);
   if (!respondingMatch) return null;
 
-  const focusedWindow = respondingMatch[1]!.trim().replace(/\s+/g, ' ');
+  const focusedWindowTitle = respondingMatch[1];
+  if (focusedWindowTitle === undefined) return null;
+  const focusedWindow = focusedWindowTitle.trim().replace(/\s+/g, ' ');
   const packageName = ANDROID_PACKAGE_PATTERN.exec(focusedWindow)?.[1];
   return {
     ...(packageName ? { package: packageName } : {}),
diff --git a/src/platforms/install-source.ts b/src/platforms/install-source.ts
@@ -266,8 +266,9 @@ function isBlockedIpv4(address: string): boolean {
   if (octets.length !== 4 || octets.some((part) => Number.isNaN(part) || part < 0 || part > 255)) {
     return false;
   }
-  const a = octets[0]!;
-  const b = octets[1]!;
+  const a = octets[0];
+  const b = octets[1];
+  if (a === undefined || b === undefined) return false;
   if (a === 10 || a === 127) return true;
   if (a === 169 && b === 254) return true;
   if (a === 172 && b >= 16 && b <= 31) return true;
@@ -323,10 +324,11 @@ async function resolveInstallableCandidate(
 
   if (stat.isDirectory()) {
     const installables = await collectMatchingPaths(candidatePath, params.isInstallablePath);
-    if (installables.length === 1) {
+    const installable = installables[0];
+    if (installable !== undefined && installables.length === 1) {
       return {
         archivePath: params.archivePath,
-        installablePath: installables[0]!,
+        installablePath: installable,
       };
     }
     if (installables.length > 1) {
@@ -341,8 +343,8 @@ async function resolveInstallableCandidate(
       candidatePath,
       (entryPath, entryStat) => entryStat.isFile() && isArchivePath(entryPath),
     );
-    if (archives.length === 1) {
-      const archive = archives[0]!;
+    const archive = archives[0];
+    if (archive !== undefined && archives.length === 1) {
       if (!params.allowArchiveExtraction) {
         throw new AppError(
           'INVALID_ARGS',
diff --git a/src/platforms/ios/apps.ts b/src/platforms/ios/apps.ts
@@ -114,8 +114,9 @@ export async function resolveIosApp(device: DeviceInfo, app: string): Promise<st
       ? await listSimulatorApps(device)
       : await listIosDeviceApps(device, 'all');
   const matches = list.filter((entry) => entry.name.toLowerCase() === trimmed.toLowerCase());
-  if (matches.length === 1) {
-    return iosAppResolutionCache.set(cacheScope, trimmed, matches[0]!.bundleId);
+  const match = matches[0];
+  if (match !== undefined && matches.length === 1) {
+    return iosAppResolutionCache.set(cacheScope, trimmed, match.bundleId);
   }
   if (matches.length > 1) {
     throw new AppError('INVALID_ARGS', `Multiple apps matched "${app}"`, { matches });
diff --git a/src/platforms/ios/install-artifact.ts b/src/platforms/ios/install-artifact.ts
@@ -120,8 +120,9 @@ async function resolveIosInstallablePath(
         installPath: path.join(payloadDir, entry.name),
         bundleName: entry.name.replace(/\.app$/i, ''),
       }));
-    if (appBundles.length === 1) {
-      return { installPath: appBundles[0]!.installPath, cleanup };
+    const appBundle = appBundles[0];
+    if (appBundle !== undefined && appBundles.length === 1) {
+      return { installPath: appBundle.installPath, cleanup };
     }
     if (appBundles.length === 0) {
       throw new AppError(
diff --git a/src/platforms/ios/macos-apps.ts b/src/platforms/ios/macos-apps.ts
@@ -40,12 +40,9 @@ export async function resolveMacOsApp(app: string): Promise<string> {
 
   const apps = await listMacApps('all');
   const matches = apps.filter((entry) => entry.name.toLowerCase() === trimmed.toLowerCase());
-  if (matches.length === 1) {
-    return macOsAppResolutionCache.set(
-      MACOS_APP_RESOLUTION_CACHE_SCOPE,
-      trimmed,
-      matches[0]!.bundleId,
-    );
+  const match = matches[0];
+  if (match !== undefined && matches.length === 1) {
+    return macOsAppResolutionCache.set(MACOS_APP_RESOLUTION_CACHE_SCOPE, trimmed, match.bundleId);
   }
   if (matches.length > 1) {
     throw new AppError('INVALID_ARGS', `Multiple apps matched "${app}"`, { matches });
diff --git a/src/replay/script.ts b/src/replay/script.ts
@@ -188,9 +188,8 @@ function parseReplayScriptLine(line: string): SessionAction | null {
   const trimmed = line.trim();
   if (trimmed.length === 0 || trimmed.startsWith('#')) return null;
   const tokens = tokenizeReplayLine(trimmed);
-  if (tokens.length === 0) return null;
-  const command = tokens[0]!;
-  const args = tokens.slice(1);
+  const [command, ...args] = tokens;
+  if (command === undefined) return null;
   if (command === 'context') return null;
 
   const action: SessionAction = {
@@ -260,8 +259,8 @@ function parseReplayScriptLine(line: string): SessionAction | null {
   if (isClickLikeCommand(command)) {
     const parsed = parseReplaySeriesFlags(command, args);
     Object.assign(action.flags, parsed.flags);
-    if (parsed.positionals.length === 0) return action;
-    const target = parsed.positionals[0]!;
+    const target = parsed.positionals[0];
+    if (target === undefined) return action;
     if (target.startsWith('@')) {
       action.positionals = [target];
       if (parsed.positionals[1]) {
@@ -301,12 +300,12 @@ function parseReplayScriptLine(line: string): SessionAction | null {
   }
 
   if (command === 'get') {
-    if (args.length < 2) {
+    const sub = args[0];
+    const target = args[1];
+    if (sub === undefined || target === undefined) {
       action.positionals = args;
       return action;
     }
-    const sub = args[0]!;
-    const target = args[1]!;
     if (target.startsWith('@')) {
       action.positionals = [sub, target];
       if (args[2]) {
diff --git a/src/utils/device.ts b/src/utils/device.ts
@@ -116,7 +116,8 @@ export async function resolveDevice(
     return match;
   }
 
-  if (candidates.length === 1) return candidates[0]!;
+  const onlyCandidate = candidates[0];
+  if (onlyCandidate !== undefined && candidates.length === 1) return onlyCandidate;
 
   if (candidates.length === 0) {
     const simulatorSetPath = context.simulatorSetPath;
@@ -138,9 +139,14 @@ export async function resolveDevice(
   }
 
   const booted = candidates.filter((d) => d.booted);
-  if (booted.length === 1) return booted[0]!;
+  const onlyBooted = booted[0];
+  if (onlyBooted !== undefined && booted.length === 1) return onlyBooted;
 
   // When multiple candidates remain equally valid, preserve discovery order from
   // the underlying platform tools rather than introducing another tie-breaker here.
-  return booted[0] ?? candidates[0]!;
+  const selected = booted[0] ?? candidates[0];
+  if (selected === undefined) {
+    throw new AppError('DEVICE_NOT_FOUND', 'No devices found', { selector });
+  }
+  return selected;
 }

Original file line number	Diff line number	Diff line change
`@@ -80,7 +80,9 @@ function findPreferredActionableDescendant(`
`80`	`80`	`if (sameRectChildren.length !== 1) {`
`81`	`81`	`break;`
`82`	`82`	`}`
`83`		`- current = sameRectChildren[0]!;`
	`83`	`+ const child = sameRectChildren[0];`
	`84`	`+ if (child === undefined) break;`
	`85`	`+ current = child;`
`84`	`86`	`}`
`85`	`87`
`86`	`88`	`return current === node ? null : current;`
Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,8 @@ export function resolveEffectiveSessionName(`
`12`	`12`	`if (sessionStore.has(requested)) return requested;`
`13`	`13`
`14`	`14`	`const sessions = sessionStore.toArray();`
`15`		`- if (sessions.length === 1) return sessions[0]!.name;`
	`15`	`+ const session = sessions[0];`
	`16`	`+ if (session !== undefined && sessions.length === 1) return session.name;`
`16`	`17`	`return requested;`
`17`	`18`	`}`
`18`	`19`