Fix unexpected end of JSON error

Summary:
This is the 6th most common error in our logging, and I just run into it after upgrading XCode. It happens when idb doesn't return any devices.

(because `''.split('\n')` results in `['']` not `[]`)

Reviewed By: jknoxville

Differential Revision: D25368759

fbshipit-source-id: 44b0e3a5dc4cf06ecdf2dff4a5692943e60d4b1d

desktop/app/src/utils/iOSContainerUtility.tsx

@@ -70,6 +70,7 @@ async function targets(idbPath: string): Promise<Array<DeviceTarget>> {
         .trim()
         .split('\n')
         .map((line) => line.trim())
+        .filter(Boolean)
         .map((line) => JSON.parse(line))
         .filter(({type}: IdbTarget) => type !== 'simulator')
         .map((target: IdbTarget) => {
@@ -83,6 +84,7 @@ async function targets(idbPath: string): Promise<Array<DeviceTarget>> {
         .toString()
         .split('\n')
         .map((line) => line.trim())
+        .filter(Boolean)
         .map((line) => /(.+) \([^(]+\) \[(.*)\]( \(Simulator\))?/.exec(line))
         .filter(notNull)
         .filter(([_match, _name, _udid, isSim]) => !isSim)