TypeError: Cannot read property 'diagnostics' of undefined at enableStatistics

[JoshuaKGoldberg]

TypeScript Version: 2.9.0-dev.20180419

Search Terms: diagnostics watch mode undefined typeerror compileroptions

Code

Start tsc -w in a directory with a tsconfig.json and files, then save a few times to launch multiple recompiles.

[12:50:50] File change detected. Starting incremental compilation...


C:\Users\Dioge\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:66653
        if (compilerOptions.diagnostics || compilerOptions.extendedDiagnostics) {
                            ^

TypeError: Cannot read property 'diagnostics' of undefined
    at enableStatistics (C:\Users\Dioge\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:66653:29)
    at watchCompilerHost.createProgram (C:\Users\Dioge\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:66629:13)
    at synchronizeProgram (C:\Users\Dioge\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:64425:38)
    at reloadFileNamesFromConfigFile (C:\Users\Dioge\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:64612:13)
    at Timeout.updateProgram [as _onTimeout] (C:\Users\Dioge\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:64593:28)
    at ontimeout (timers.js:466:11)
    at tryOnTimeout (timers.js:304:5)
    at Timer.listOnTimeout (timers.js:267:5)

Edit: temporary workaround: defaulting compilerOptions to {} in that function stops any errors.