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# User Interaction Errors
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Error classes for user interaction scenarios including user refusals, permission issues, and input validation failures.
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## Capabilities
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### User Refusal Errors
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Errors for when users explicitly refuse or cancel operations on the device.
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```typescript { .api }
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const UserRefusedOnDevice: CustomErrorFunc;
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const UserRefusedAddress: CustomErrorFunc;
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const UserRefusedFirmwareUpdate: CustomErrorFunc;
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const UserRefusedAllowManager: CustomErrorFunc;
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const UserRefusedDeviceNameChange: CustomErrorFunc;
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```
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**Usage Examples:**
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```typescript
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import { 
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  UserRefusedOnDevice,
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  UserRefusedAddress,
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  UserRefusedFirmwareUpdate,
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  UserRefusedAllowManager
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} from "@ledgerhq/errors";
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// Handle transaction refusal
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try {
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  await signTransaction();
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} catch (error) {
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  if (error instanceof UserRefusedOnDevice) {
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    console.log("User cancelled transaction on device");
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    showMessage("Transaction was cancelled by user");
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  }
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}
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// Handle address verification refusal
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try {
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  await verifyAddress();
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} catch (error) {
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  if (error instanceof UserRefusedAddress) {
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    console.log("User refused to verify address");
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  }
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}
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// Handle firmware update refusal
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if (userResponse === "denied") {
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  throw new UserRefusedFirmwareUpdate("User declined firmware update");
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}
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// Handle manager access refusal
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if (!allowManagerAccess) {
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  throw new UserRefusedAllowManager("User denied manager access permissions");
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}
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```
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### Permission and Access Errors
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Errors related to system permissions and hardware access.
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```typescript { .api }
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const NoAccessToCamera: CustomErrorFunc;
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const CantScanQRCode: CustomErrorFunc;
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const PairingFailed: CustomErrorFunc;
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```
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**Usage Examples:**
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```typescript
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import { 
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  NoAccessToCamera,
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  CantScanQRCode,
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  PairingFailed
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} from "@ledgerhq/errors";
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// Handle camera permission
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try {
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  await requestCameraAccess();
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} catch (error) {
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  throw new NoAccessToCamera("Camera access required for QR code scanning");
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}
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// Handle QR code scanning issues
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try {
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  const qrData = await scanQRCode();
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} catch (error) {
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  if (error instanceof CantScanQRCode) {
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    console.log("Unable to scan QR code - check lighting and positioning");
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  }
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}
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// Handle device pairing failure
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try {
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  await pairDevice();
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} catch (error) {
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  if (error instanceof PairingFailed) {
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    console.log("Device pairing failed - please try again");
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    console.log("Ensure device is in pairing mode and nearby");
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  }
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}
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```
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### Password and Authentication Errors
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Errors related to password validation and authentication.
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```typescript { .api }
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const PasswordsDontMatchError: CustomErrorFunc;
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const PasswordIncorrectError: CustomErrorFunc;
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```
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**Usage Examples:**
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```typescript
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import { 
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  PasswordsDontMatchError,
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  PasswordIncorrectError
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} from "@ledgerhq/errors";
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// Handle password confirmation
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function validatePasswordConfirmation(password: string, confirmPassword: string) {
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  if (password !== confirmPassword) {
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    throw new PasswordsDontMatchError("Password confirmation does not match");
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  }
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}
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// Handle incorrect password
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try {
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  await authenticateUser(password);
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} catch (error) {
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  if (error instanceof PasswordIncorrectError) {
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    console.log("Incorrect password entered");
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    attemptCount++;
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    if (attemptCount >= 3) {
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      lockAccount();
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    }
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  }
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}
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// Example usage in form validation
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function handlePasswordForm(data: { password: string; confirmPassword: string }) {
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  try {
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    validatePasswordConfirmation(data.password, data.confirmPassword);
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    console.log("Password validation successful");
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  } catch (error) {
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    if (error instanceof PasswordsDontMatchError) {
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      showError("Passwords must match");
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    }
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  }
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}
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```