bridge.scanAccountsOnDevice needs to return Observable for safety

src/bridge/EthereumJSBridge.js

@@ -156,7 +156,8 @@ const fetchCurrentBlock = (perCurrencyId => currency => {
 })({})
 
 const EthereumBridge: WalletBridge<Transaction> = {
-  scanAccountsOnDevice(currency, deviceId, { next, complete, error }) {
+  scanAccountsOnDevice: (currency, deviceId) =>
+    Observable.create(o => {
       let finished = false
       const unsubscribe = () => {
         finished = true
@@ -251,22 +252,22 @@ const EthereumBridge: WalletBridge<Transaction> = {
                 .send({ currencyId: currency.id, devicePath: deviceId, path: freshAddressPath })
                 .toPromise()
               const r = await stepAddress(index, res, isStandard)
-            if (r.account) next(r.account)
+              if (r.account) o.next(r.account)
               if (r.complete) {
                 break
               }
             }
           }
-        complete()
+          o.complete()
         } catch (e) {
-        error(e)
+          o.error(e)
         }
       }
 
       main()
 
-    return { unsubscribe }
-  },
+      return unsubscribe
+    }),
 
   synchronize: ({ freshAddress, blockHeight, currency, operations }) =>
     Observable.create(o => {

src/bridge/LibcoreBridge.js

@@ -79,14 +79,13 @@ const getFees = async (a, transaction) => {
 }
 
 const LibcoreBridge: WalletBridge<Transaction> = {
-  scanAccountsOnDevice(currency, devicePath, observer) {
+  scanAccountsOnDevice(currency, devicePath) {
     return libcoreScanAccounts
       .send({
         devicePath,
         currencyId: currency.id,
       })
       .pipe(map(decodeAccount))
-      .subscribe(observer)
   },
 
   synchronize: account =>

src/bridge/RippleJSBridge.js

@@ -239,7 +239,8 @@ const getServerInfo = (map => endpointConfig => {
 })({})
 
 const RippleJSBridge: WalletBridge<Transaction> = {
-  scanAccountsOnDevice(currency, deviceId, { next, complete, error }) {
+  scanAccountsOnDevice: (currency, deviceId) =>
+    Observable.create(o => {
       let finished = false
       const unsubscribe = () => {
         finished = true
@@ -282,7 +283,7 @@ const RippleJSBridge: WalletBridge<Transaction> = {
                 // account does not exist in Ripple server
                 // we are generating a new account locally
                 if (!legacy) {
-                next({
+                  o.next({
                     id: accountId,
                     xpub: '',
                     name: getNewAccountPlaceholderName(currency, index),
@@ -331,12 +332,12 @@ const RippleJSBridge: WalletBridge<Transaction> = {
                 lastSyncDate: new Date(),
               }
               account.operations = transactions.map(txToOperation(account))
-            next(account)
+              o.next(account)
             }
           }
-        complete()
+          o.complete()
         } catch (e) {
-        error(e)
+          o.error(e)
         } finally {
           api.disconnect()
         }
@@ -344,8 +345,8 @@ const RippleJSBridge: WalletBridge<Transaction> = {
 
       main()
 
-    return { unsubscribe }
-  },
+      return unsubscribe
+    }),
 
   synchronize: ({ endpointConfig, freshAddress, blockHeight }) =>
     Observable.create(o => {

src/bridge/UnsupportedBridge.js

@@ -10,10 +10,10 @@ const UnsupportedBridge: WalletBridge<*> = {
       o.error(genericError)
     }),
 
-  scanAccountsOnDevice(currency, deviceId, { error }) {
-    Promise.resolve(genericError).then(error)
-    return { unsubscribe() {} }
-  },
+  scanAccountsOnDevice: () =>
+    Observable.create(o => {
+      o.error(genericError)
+    }),
 
   pullMoreOperations: () => Promise.reject(genericError),
 

src/bridge/makeMockBridge.js

@@ -75,13 +75,14 @@ function makeMockBridge(opts?: Opts): WalletBridge<*> {
         }
       }),
 
-    scanAccountsOnDevice(currency, deviceId, { next, complete, error }) {
+    scanAccountsOnDevice: (currency, deviceId) =>
+      Observable.create(o => {
         let unsubscribed = false
 
         async function job() {
           if (Math.random() > scanAccountDeviceSuccessRate) {
             await delay(1000)
-          if (!unsubscribed) error(new Error('scan failed'))
+            if (!unsubscribed) o.error(new Error('scan failed'))
             return
           }
           const nbAccountToGen = 3
@@ -92,9 +93,9 @@ function makeMockBridge(opts?: Opts): WalletBridge<*> {
               currency,
             })
             account.unit = currency.units[0]
-          if (!unsubscribed) next(account)
+            if (!unsubscribed) o.next(account)
           }
-        if (!unsubscribed) complete()
+          if (!unsubscribed) o.complete()
         }
 
         job()
@@ -104,7 +105,7 @@ function makeMockBridge(opts?: Opts): WalletBridge<*> {
             unsubscribed = true
           },
         }
-    },
+      }),
 
     pullMoreOperations: async (_accountId, _desiredCount) => {
       await delay(1000)

src/bridge/types.js

@@ -33,11 +33,7 @@ export interface WalletBridge<Transaction> {
   // the scan can stop once all accounts are discovered.
   // the function returns a Subscription and you MUST stop everything if it is unsubscribed.
   // TODO return Observable
-  scanAccountsOnDevice(
-    currency: Currency,
-    deviceId: DeviceId,
-    observer: Observer<Account>,
-  ): Subscription;
+  scanAccountsOnDevice(currency: Currency, deviceId: DeviceId): Observable<Account>;
 
   // synchronize an account. meaning updating the account object with latest state.
   // function receives the initialAccount object so you can actually know what the user side currently have

src/components/modals/AddAccounts/steps/03-step-import.js

@@ -72,7 +72,7 @@ class StepImport extends PureComponent<StepProps> {
       // TODO: use the real device
       const devicePath = currentDevice.path
 
-      this.scanSubscription = bridge.scanAccountsOnDevice(currency, devicePath, {
+      this.scanSubscription = bridge.scanAccountsOnDevice(currency, devicePath).subscribe({
         next: account => {
           const { scannedAccounts, checkedAccountsIds, existingAccounts } = this.props
           const hasAlreadyBeenScanned = !!scannedAccounts.find(a => account.id === a.id)