Could not find iPhone 6 simulator


Recently, there is something wrong with the old project that needs to be dealt with. After running the startup command, the following error is reported, indicating that the iPhone 6 simulator cannot be found.

react-native run-ios

Owaiss-Mac:pdm owaisahmed$ react-native run-ios
Found Xcode project pdm.xcodeproj

Could not find iPhone 6 simulator

Error: Could not find iPhone 6 simulator
    at resolve (/Users/fantuan/Documents/react-native-projects/pdm/node_modules/react-native/local-cli/runIOS/runIOS.js:149:13)
    at new Promise (<anonymous>)
    at runOnSimulator (/Users/fantuan/Documents/react-native-projects/pdm/node_modules/react-native/local-cli/runIOS/runIOS.js:134:10)
    at Object.runIOS [as func] (/Users/fantuan/Documents/react-native-projects/pdm/node_modules/react-native/local-cli/runIOS/runIOS.js:106:12)
    at Promise.resolve.then (/Users/fantuan/Documents/react-native-projects/pdm/node_modules/react-native/local-cli/cliEntry.js:117:22)

When the old project was the version of the current project a year ago, it was still 0.57. During this period, the system version of the working computer was upgraded to 10.14.6, and the version of Xcode was upgraded to 10.3. The specific environment information of the current project can be viewed by using the following command:

React Native Environment Info:
      OS: macOS 10.14.6
      CPU: (8) x64 Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
      Memory: 26.40 MB / 16.00 GB
      Shell: 5.3 - /bin/zsh
      Node: 10.14.1 - ~/.nvm/versions/node/v10.14.1/bin/node
      Yarn: 1.13.0 - ~/.nvm/versions/node/v10.14.1/bin/yarn
      npm: 6.4.1 - ~/.nvm/versions/node/v10.14.1/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
      iOS SDK:
        Platforms: iOS 12.4, macOS 10.14, tvOS 12.4, watchOS 5.3
      Android SDK:
        API Levels: 23, 25, 26, 27, 28, 29
        Build Tools: 23.0.1, 23.0.3, 25.0.2, 25.0.3, 26.0.3, 27.0.3, 28.0.0, 28.0.2, 28.0.3, 29.0.2
        System Images: android-23 | Intel x86 Atom, android-23 | Intel x86 Atom_64, android-23 | Google APIs Intel x86 Atom_64, android-29 | Google APIs Intel x86 Atom
      Android Studio: 3.1 AI-173.4720617
      Xcode: 10.3/10G8 - /usr/bin/xcodebuild
      react: 16.5.0 => 16.5.0
      react-native: 0.57.0 => 0.57.0
      react-native-cli: 2.0.1
      react-native-create-library: 3.1.2

After a review, it was found that the upgrade of Xcode version to 10 resulted.
The solution is as follows:
1. Open the project node [modules / react native / local cli / runios / findmatchingsimulator.js file
2. Modify line 31 of the document

if (!version.startsWith('iOS') && !version.startsWith('tvOS')) {

Is the following code

if (!version.startsWith('') 
    && !version.startsWith('')) {

Note for hematemesis:
For react native project development, please do not upgrade Xcode and other compilers easily, unless you are proficient.

Welcome everyone to pay attention to my public address: Junwei said, regularly push development technology.