`react-native run-ios` returns Error: Could not find iPhone X simulator

Question

whenever I run react-native run-ios, I get

Could not find iPhone X simulator

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

however, when I run on Xcode, it works fine

{
  "devicetypes" : [
    {
      "name" : "iPhone 4s",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 4s.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-4s"
    },
    {
      "name" : "iPhone 5",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 5.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-5"
    },
    {
      "name" : "iPhone 5s",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 5s.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-5s"
    },
    {
      "name" : "iPhone 6",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 6.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-6"
    },
    {
      "name" : "iPhone 6 Plus",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 6 Plus.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus"
    },
    {
      "name" : "iPhone 6s",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 6s.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-6s"
    },
    {
      "name" : "iPhone 6s Plus",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 6s Plus.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-6s-Plus"
    },
    {
      "name" : "iPhone 7",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 7.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-7"
    },
    {
      "name" : "iPhone 7 Plus",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 7 Plus.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-7-Plus"
    },
    {
      "name" : "iPhone 8",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 8.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-8"
    },
    {
      "name" : "iPhone 8 Plus",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone 8 Plus.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-8-Plus"
    },
    {
      "name" : "iPhone SE",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone SE.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-SE"
    },
    {
      "name" : "iPhone X",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone X.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-X"
    },
    {
      "name" : "iPhone Xs",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone Xs.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-XS"
    },
    {
      "name" : "iPhone Xs Max",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone Xs Max.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-XS-Max"
    },
    {
      "name" : "iPhone Xʀ",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPhone Xʀ.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPhone-XR"
    },
    {
      "name" : "iPad 2",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad 2.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-2"
    },
    {
      "name" : "iPad Retina",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Retina.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Retina"
    },
    {
      "name" : "iPad Air",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Air.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Air"
    },
    {
      "name" : "iPad Air 2",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Air 2.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Air-2"
    },
    {
      "name" : "iPad (5th generation)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad (5th generation).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad--5th-generation-"
    },
    {
      "name" : "iPad Pro (9.7-inch)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Pro (9.7-inch).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Pro--9-7-inch-"
    },
    {
      "name" : "iPad Pro (12.9-inch)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Pro (12.9-inch).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Pro"
    },
    {
      "name" : "iPad Pro (12.9-inch) (2nd generation)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Pro (12.9-inch) (2nd generation).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Pro--12-9-inch---2nd-generation-"
    },
    {
      "name" : "iPad Pro (10.5-inch)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Pro (10.5-inch).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Pro--10-5-inch-"
    },
    {
      "name" : "iPad (6th generation)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad (6th generation).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad--6th-generation-"
    },
    {
      "name" : "iPad Pro (11-inch)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Pro (11-inch).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Pro--11-inch-"
    },
    {
      "name" : "iPad Pro (12.9-inch) (3rd generation)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/iPad Pro (12.9-inch) (3rd generation).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.iPad-Pro--12-9-inch---3rd-generation-"
    },
    {
      "name" : "Apple TV",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/AppleTVOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple TV.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-TV-1080p"
    },
    {
      "name" : "Apple TV 4K",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/AppleTVOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple TV 4K.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-TV-4K-4K"
    },
    {
      "name" : "Apple TV 4K (at 1080p)",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/AppleTVOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple TV 4K (at 1080p).simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-TV-4K-1080p"
    },
    {
      "name" : "Apple Watch - 38mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch - 38mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-38mm"
    },
    {
      "name" : "Apple Watch - 42mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch - 42mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-42mm"
    },
    {
      "name" : "Apple Watch Series 2 - 38mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch Series 2 - 38mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-2-38mm"
    },
    {
      "name" : "Apple Watch Series 2 - 42mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch Series 2 - 42mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-2-42mm"
    },
    {
      "name" : "Apple Watch Series 3 - 38mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch Series 3 - 38mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-3-38mm"
    },
    {
      "name" : "Apple Watch Series 3 - 42mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch Series 3 - 42mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-3-42mm"
    },
    {
      "name" : "Apple Watch Series 4 - 40mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch Series 4 - 40mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-4-40mm"
    },
    {
      "name" : "Apple Watch Series 4 - 44mm",
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/DeviceTypes\/Apple Watch Series 4 - 44mm.simdevicetype",
      "identifier" : "com.apple.CoreSimulator.SimDeviceType.Apple-Watch-Series-4-44mm"
    }
  ],
  "runtimes" : [
    {
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/iPhoneOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/Runtimes\/iOS.simruntime",
      "availabilityError" : "",
      "buildversion" : "16B91",
      "availability" : "(available)",
      "isAvailable" : true,
      "identifier" : "com.apple.CoreSimulator.SimRuntime.iOS-12-1",
      "version" : "12.1",
      "name" : "iOS 12.1"
    },
    {
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/AppleTVOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/Runtimes\/tvOS.simruntime",
      "availabilityError" : "",
      "buildversion" : "16J602",
      "availability" : "(available)",
      "isAvailable" : true,
      "identifier" : "com.apple.CoreSimulator.SimRuntime.tvOS-12-1",
      "version" : "12.1",
      "name" : "tvOS 12.1"
    },
    {
      "bundlePath" : "\/Applications\/Xcode.app\/Contents\/Developer\/Platforms\/WatchOS.platform\/Developer\/Library\/CoreSimulator\/Profiles\/Runtimes\/watchOS.simruntime",
      "availabilityError" : "",
      "buildversion" : "16R591",
      "availability" : "(available)",
      "isAvailable" : true,
      "identifier" : "com.apple.CoreSimulator.SimRuntime.watchOS-5-1",
      "version" : "5.1",
      "name" : "watchOS 5.1"
    }
  ],
  "devices" : {
    "com.apple.CoreSimulator.SimRuntime.watchOS-5-1" : [
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple Watch Series 2 - 38mm",
        "udid" : "01AFDEF7-63B6-465C-A02A-44EE4A07EABA",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple Watch Series 2 - 42mm",
        "udid" : "BE62C985-DEE2-46EC-8962-A582D537EEE0",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple Watch Series 3 - 38mm",
        "udid" : "078BF157-30FA-41D1-94FA-6B1686E03085",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple Watch Series 3 - 42mm",
        "udid" : "E4CE652E-0185-4C59-B965-BED5FCEE7C76",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple Watch Series 4 - 40mm",
        "udid" : "6621323A-A9DE-4BCB-AC97-54C8C33B0158",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple Watch Series 4 - 44mm",
        "udid" : "D89037A3-66A0-43C1-90BA-E7C76CA0D724",
        "availabilityError" : ""
      }
    ],
    "com.apple.CoreSimulator.SimRuntime.tvOS-12-1" : [
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple TV",
        "udid" : "AFAA21B8-BD4A-45EA-B0FF-E9915FE9B926",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple TV 4K",
        "udid" : "EBB88F2E-CFFE-4981-A736-7A7C0B85643D",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "Apple TV 4K (at 1080p)",
        "udid" : "F0B73E8A-986E-447E-B37A-2F46096DEFF6",
        "availabilityError" : ""
      }
    ],
    "com.apple.CoreSimulator.SimRuntime.iOS-12-1" : [
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 5s",
        "udid" : "F870B7FA-6DDA-4336-89AD-68A402844188",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 5s",
        "udid" : "6627ADE5-F8C1-4AE5-BD6F-3AEDDC0B7B63",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 6",
        "udid" : "05574997-ACAD-40CA-A3D7-5624D53F00FA",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 6 Plus",
        "udid" : "93237078-CA6D-4F97-93F9-779809700018",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 6s",
        "udid" : "9B50FE18-4F49-4EA4-80F0-DF498A667D33",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 6s Plus",
        "udid" : "D4640B6D-97DC-4CA1-BE63-C5403159A3D4",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 7",
        "udid" : "6E9EEC00-3291-42B4-B04A-BA3487F9CD5F",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 7 Plus",
        "udid" : "6DA1C3CF-1D1F-4DEF-9B74-2C40D5FB5881",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 8",
        "udid" : "E19386B9-469A-450B-9CD2-B4FE8687DCF9",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone 8 Plus",
        "udid" : "6D36DF76-8ED9-41A2-9E1A-0BA48B92C26E",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone SE",
        "udid" : "EE4818DF-F817-4441-8A1C-BE1B99303E10",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone X",
        "udid" : "85B78A8F-C32B-4493-BDD1-65ECA3F77C86",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone X",
        "udid" : "CA12C337-4F66-4C6C-ACE5-7F7EACCBC39A",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone XS",
        "udid" : "8BBCE315-2F4C-4132-8E53-28AF52401C8E",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone XS Max",
        "udid" : "4E77C62F-AB1F-4EDE-839B-53F70CAFC79E",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPhone XR",
        "udid" : "28D12ABE-3355-4862-960A-0FE5FFE41C7B",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Air",
        "udid" : "94485C88-BCEB-456A-95DC-5F8C3DA8D181",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Air 2",
        "udid" : "CF2C787D-A378-4AB9-B334-F7B24E94AF4D",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad (5th generation)",
        "udid" : "DFE602A5-EC68-4585-8AB0-C045A9843D29",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Pro (9.7-inch)",
        "udid" : "5A3F3EAC-F788-49F1-A753-5D34A9990F0B",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Pro (12.9-inch)",
        "udid" : "EF6EBE34-0A85-4FF0-8A45-7BA418A0CC0C",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Pro (12.9-inch) (2nd generation)",
        "udid" : "FBA940F8-FD85-4D5E-A570-EB4F3A56E1F9",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Pro (10.5-inch)",
        "udid" : "8AE4AAED-ECE0-4984-9679-8D3022064692",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad (6th generation)",
        "udid" : "1121363D-EF49-4AC0-9E46-5C30318A24A2",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Pro (11-inch)",
        "udid" : "038FECC0-8711-46E3-B601-8F88F2F4AD7D",
        "availabilityError" : ""
      },
      {
        "availability" : "(available)",
        "state" : "Shutdown",
        "isAvailable" : true,
        "name" : "iPad Pro (12.9-inch) (3rd generation)",
        "udid" : "12DC911F-2F45-4767-BC1A-6F1D0C8D9F3D",
        "availabilityError" : ""
      }
    ]
  },
  "pairs" : {
    "C9B69F4A-6A9D-44F3-A6BC-56BFA2F8B83F" : {
      "watch" : {
        "name" : "Apple Watch Series 4 - 44mm",
        "udid" : "D89037A3-66A0-43C1-90BA-E7C76CA0D724",
        "state" : "Shutdown"
      },
      "phone" : {
        "name" : "iPhone XS Max",
        "udid" : "4E77C62F-AB1F-4EDE-839B-53F70CAFC79E",
        "state" : "Shutdown"
      },
      "state" : "(active, disconnected)"
    },
    "5327B65F-29E7-42D0-9861-FF31428F3218" : {
      "watch" : {
        "name" : "Apple Watch Series 4 - 40mm",
        "udid" : "6621323A-A9DE-4BCB-AC97-54C8C33B0158",
        "state" : "Shutdown"
      },
      "phone" : {
        "name" : "iPhone XS",
        "udid" : "8BBCE315-2F4C-4132-8E53-28AF52401C8E",
        "state" : "Shutdown"
      },
      "state" : "(active, disconnected)"
    }
  }

Answer 1

In my case the problem was that after an xcode update the simulator got removed and I had to create it manually (as this new xcode Version did not had it as a default)

You could check if it is as device listed here:

xcrun simctl list devices

If it's under the "Unavailable" title (because you're missing the iOS version), you can create one with you current version, or download the expected runtime.

For that go to XCode->Window->Devices and Simulators and hit on the plus button, to create your simulator with model an iOS version as depicted here:

That solved my problem.

Answer 2

What fixed it for me was not having Xcode command lines tools set (xcrun simctl was failing.) If you just re-installed Xcode, you might have this issue.

See this post on how to set the command line tools. After, try running react-native run-ios --simulator="iPhone 11" (or whatever your simulator name is).

Answer 3

I had the same problem

npm audit fix

this worked for me

Answer 4

To fix this error, simply reinstall project & node modules using npm

npm install

Then it will show a list of warnings, and to fix them use the following command:

npm audit fix

This should fix everything, and allow you to run iOS emulator react-native run-ios

Answer 5

I encountered this issue after trying to upgrade React Native from 0.59.8 to 0.59.9.

It turns out (based the above answers), we need to update @react-native-community/cli module:

1. Remove it from lockfile (yarn.lock or package-lock.json)
2. Run yarn or npm install to install it again.

reference: https://github.com/react-native-community/rn-diff-purge/issues/21#issuecomment-507645945

Answer 6

I encountered the same error when i upgraded my Xcode 10 to Xcode 11, But specifying the simulator version happens to be a quick fix for me.

First list all available ios emulator with

  xcrun simctl list devices | grep iPhone | grep -v unavailable | cut -d'(' -f1

Result

Then select one to run react-native with, e.g

 react-native run-ios --simulator='iPhone 11 Pro Max'

Answer 7

PROBLEM

If you try this with the latest Xcode (11), there is no iPhone X!

Run Simulator by itself, in the top menu, look under Hardware, Device, iOS 13.0. You will see there is:

• iPhone 8
• iPhone 8 Plus
• iPhone XS
• iPhone XS Max
• iPhone XR
• ... and some iPads

When you execute run-ios, react-native is designed to match a requested device.

The internally hard coded default is iPhone X.

The function that tries to match the requested device is in:

/node_modules/@react-native-community/cli-platform-ios/build/commands/runIOS/findMatchingSimulator.js

This function is designed so you can give it a device, and an optional version number.

If the given device and version cannot be found, it will return a match using the first device in the list by default.

But... in reality, the first device is a watch, and any watch is excluded from matching, so this function will return null.

SOLUTION 1 - Use an existing Xcode device

Run Simulator first by itself, as described above, and make a note of which iPhone or iPad you want.

Then pass this name as an optional argument the the run-ios command line command as follows:

react-native run-ios --simulator="iPhone 8"

SOLUTION 2 - Add New Xcode iOS Device

According to Xcode 11 Release Notes:

"Xcode no longer creates every available iOS simulator device by default. Instead a set of the most commonly used devices are created. To create other devices — or multiple instances of a device — open the Devices window, select Simulators, click the + button, enter a name, and select the relevant device type and OS version. In Terminal, execute the xcrun simctl create command, for example xcrun simctl create "My iPhone 7" "iPhone 7" iOS13.0. (49428617)"

In Xcode, you need to add a new device called "iPhone X".

Also I answered here: React Native Issue #2328

Answer 8

For me, I had to update React Native to 0.60 by running npx react-native-git-upgrade.

Answer 9

In my case, i have tried others above solution but nothing worked.

Then i try upgrading react-native from 0.59.5 to 0.59.10 then it's solved

Answer 10

For Xcode 11.2 and iOS 13.2 here are changes i've done to run the app in simulator

in findMatchingSimulator.js

line 43:

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

to

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

line

line 52

if (
    simulator.availability !== '(available)' &&
    simulator.isAvailable !== 'YES'
  ) {
    continue;
  }

to

if (
    simulator.isAvailable != true
  ) {
    continue;
  }

P.S.

First day on React project ad already lowing it! (no)

Answer 11

After I updated Xcode to version 11, I encountered the same problem.

A solution can be to add the iPhone X simulator into your list.

• Choose simulator -> Hardware -> Manage Devices (you will see a popup)

• Choose "Simulators" -> (left bottom corner) +(the plus icon, next to "Filter") then add a new simulator,

• Simulator Name: iPhone X Device Type: Choose iPhone X.

It worked for me

Answer 12

My problem was that iPhone X simulator was not installed

You can check what simulators are installed with

xcrun simctl list devices | grep iPhone | grep -v unavailable | cut -d'(' -f1

Then run

react-native run-ios --simulator="iPhone Xs"

Answer 13

change /node_modules/@react-native-community/cli-platform-ios/build/commands/runIOS/index.js

file

options: [{
    name: '--simulator [string]',
    description: 'Explicitly set simulator to use. Optionally include iOS version between' + 'parenthesis at the end to match an exact version: "iPhone 6 (10.0)"',
    default: 'iPhone X'
  }

to

options: [{
    name: '--simulator [string]',
    description: 'Explicitly set simulator to use. Optionally include iOS version between' + 'parenthesis at the end to match an exact version: "iPhone 6 (10.0)"',
    default: 'iPhone 8'
  }

Answer 14

I also did not have iPhone X installed as a simulator on Xcode. All I had to do was add the iPhone X as a new simulator in Xcode and all is well.

In Xcode: Go to Window then Devices and Simulators. Click the simulators tab. Click the + button on the bottom left corner and add the iPhone X.

I hope this fix is as easy for you as it was for me.

Answer 15

There is no iPhone X simulator on your machine, most probably because you updated Xcode. You can simply pass the name of the available simulator like below:

react-native run-ios --simulator="iPhone 11"

For checking available simulators you can open Xcode and check on device list as shown below:

Answer 16

easy fix...

Xcode -> preferences -> components install ios 12.2 sumulator

Answer 17

I'm having the same issue each time I update Xcode.
I run this command:

sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService

Then I run react-native run-ios again.

Answer 18

Just reboot your computer and run command again.

Answer 19

I faced the issue when I updated Xcode. All the simulators were not available/uninstalled. I am installing them again.

Answer 20

With react-native-cli 2.0.1, you may want to just rename your simulator. By default Xcode will name some devices in the format <DeviceName> (<DeviceSize>). However this version of the CLI interprets anything in parentheses as the iOS version.

When trying to run a simulator named iPad Pro (10.5-inch), I was able to get it to run by simply renaming the simulator to iPad Pro [10.5-inch].

You can rename simulators by using the Simulator app's Hardware->Device->Manage Devices... menu, and right-clicking one of your simulators (in Xcode 10.2.1)

Answer 21

if could not found simulator still persists after replacing following lines of code in runSimulator.js.

Path for runSimulator.js -> /node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js

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

with this one

if ( !version.startsWith('com.apple.CoreSimulator.SimRuntime.iOS') && !version.startsWith('com.apple.CoreSimulator.SimRuntime.tvOS') ) { continue; }

comment following lines after replacing

if ( simulator.availability !== '(available)' && simulator.isAvailable !== 'YES' ) { continue; }

It will launch iPhone simulator without any issue.

and 2nd approach after updating to XCode 11

Xcode 11 xcrun returns true or false and not YES or NO for isAvailable property as before. You can check that using the following command

xcrun simctl list devices --json 

above command will print all available devices like following

"com.apple.CoreSimulator.SimRuntime.iOS-12-2" : [
  {
    "state" : "Booted",
    "isAvailable" : true,
    "name" : "iPhone X",
    "udid" : "E53748D1-628B-4A99-A419-4D7AE7CE4745"
  }
]

Replace YES with true in following code

if ( simulator.availability !== '(available)' && simulator.isAvailable !== 'YES' ) { continue; }

like this

if ( simulator.availability !== '(available)' && simulator.isAvailable !== true ) { continue; }

Answer 22

after update to Xcode 11 xcrun returns true or false and not YES or NO as before.

goto /node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js and in

find

if (
   simulator.availability !== '(available)' &&
   simulator.isAvailable !== 'YES'
 ) {
  continue;
}

and change it to

if (
   simulator.availability !== '(available)' &&
   simulator.isAvailable !== true
 ) {
  continue;
}

Answer 23

in my case i run the script: sed -i '' 's/startsWith/includes/g' node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js and it worked. also suitable for people who can't update react-native

Answer 24

Open the file /node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js

!version.startsWith('iOS') - > !version.includes('iOS')

Answer 25

Edited: I copied your devices section of your output JSON and embedded to my own /node_modules/react-native/local-cli/runIOS/runIOS.js

function runOnSimulator(xcodeProject, args, scheme) {
return new Promise(resolve => {
    try {
        var simulators = {devices section of your json}; //Here
    } catch (e) {
        console.log("e", e);
        throw new Error('Could not parse the simulator list output');
    }

    const selectedSimulator = findMatchingSimulator(simulators, args.simulator);
    console.log("selected", selectedSimulator);
    if (!selectedSimulator) {
        throw new Error(`Could not find ${args.simulator} simulator`);
    }
    ...

And finally, it gave the same error as yours. So I figured out that parsing version of devices different. In your devices, version is;

"com.apple.CoreSimulator.SimRuntime.tvOS-12-1" //for tvOS
"com.apple.CoreSimulator.SimRuntime.iOS-12-1" // for iOS

but in react-native checks this version values like this(/node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js);

// Making sure the version of the simulator is an iOS or tvOS (Removes Apple Watch, etc)
if (!version.startsWith('iOS') && !version.startsWith('tvOS')) {
    continue;
}

So react-native can not recognize.
If we change this code with this;

// Making sure the version of the simulator is an iOS or tvOS (Removes Apple Watch, etc)
if (!version.startsWith('com.apple.CoreSimulator.SimRuntime.iOS') && !version.startsWith('com.apple.CoreSimulator.SimRuntime.tvOS')) {
    continue;
}

the problem was solved. I checked that with your JSON data in my computer and it worked.

Answer 26

Temporary fix:

Step 1: Open the file /node_modules/react-native/local-cli/runIOS/findMatchingSimulator.js

Step 2: Change a line of code, from this:

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

to this:

if (!version.startsWith('com.apple.CoreSimulator.SimRuntime.iOS') && !version.startsWith('com.apple.CoreSimulator.SimRuntime.tvOS')) {
  continue;
}

Step 3: Run react-native run-ios (you might need to run it twice, and don't forget to kill the Metro Bundler [the console that's running in the background] if it's running from your previous unsuccessful build!)

The problem was that after an update to Xcode - the simulator namespaces were added to the devices' versions list. The React Native build wasn't expecting these namespaces - hence the build break.