TypeError: Cannot read property 'length' of undefined
    at unescapeLeadingUnderscores (tsserver.js:9007:18)
    at Object.idText (tsserver.js:9011:16)
    at IdentifierObject.get [as text] (tsserver.js:79132:27)
    at tryGetGlobalSymbols (tsserver.js:65594:126)
    at getCompletionData (tsserver.js:65478:22)
    at Object.getCompletionsAtPosition (tsserver.js:65060:34)
    at Object.getCompletionsAtPosition (tsserver.js:79777:35)
    at IOSession.Session.getCompletions (tsserver.js:86199:64)
    at Session.handlers.ts.createMapFromTemplate._a.(anonymous function) (tsserver.js:85311:61)
    at tsserver.js:86669:88
    at IOSession.Session.executeWithRequestId (tsserver.js:86660:28)
    at IOSession.Session.executeCommand (tsserver.js:86669:33)
    at IOSession.Session.onMessage (tsserver.js:86689:35)
    at Interface.<anonymous> (tsserver.js:87881:27)
    at emitOne (events.js:96:13)
    at Interface.emit (events.js:191:7)
    at Interface._onLine (readline.js:241:10)
    at Interface._normalWrite (readline.js:384:12)
    at Socket.ondata (readline.js:101:10)
    at emitOne (events.js:96:13)
    at Socket.emit (events.js:191:7)
    at readableAddChunk (_stream_readable.js:178:18)
    at Socket.Readable.push (_stream_readable.js:136:10)
    at Pipe.onread (net.js:560:20)