title: No overload matches this call. Type 'string' is not assignable to type 'Signals'
body: <p>I am using typescript to build a microservice and handling signals as well. The code was working fine till a few days ago but recently it started throwing errors. Couldn't find a fix for the issue.</p>
  <p>code for handling signals. It is just part of the file.
  <code>src/main.ts</code></p>
  <pre><code>  enum signals {
      SIGHUP = 1,
      SIGINT = 2,
      SIGTERM = 15
    }
    const shutdown = (signal, value) =&gt; {
      logger.warn(&quot;shutdown!&quot;)
      Db.closeAll()
      process.exit(value)
    }
    Object.values(signals).forEach(signal =&gt; {
      process.on(signal, () =&gt; {
        logger.warn(`process received a ${signal} signal`)
        shutdown(signal, signals[signal])
      })
    })
  </code></pre>
  <p>When I do <code>ts-node src/main.ts</code> The following error throws and exits.</p>
  <pre><code>
  /home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:245
      return new TSError(diagnosticText, diagnosticCodes)
             ^
  TSError: ⨯ Unable to compile TypeScript:
  src/main.ts:35:16 - error TS2769: No overload matches this call.
    The last overload gave the following error.
      Argument of type 'string | signals' is not assignable to parameter of type 'Signals'.
        Type 'string' is not assignable to type 'Signals'.
  
  35     process.on(signal, () =&gt; {
                    ~~~~~~
  
    node_modules/@types/node/base.d.ts:653:9
      653         on(event: Signals, listener: SignalsListener): this;
                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      The last overload is declared here.
  
      at createTSError (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:245:12)
      at reportTSError (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:249:19)
      at getOutput (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:362:34)
      at Object.compile (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:395:32)
      at Module.m._compile (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:473:43)
      at Module._extensions..js (module.js:663:10)
      at Object.require.extensions.(anonymous function) [as .ts] (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:476:12)
      at Module.load (module.js:565:32)
      at tryModuleLoad (module.js:505:12)
      at Function.Module._load (module.js:497:3)
  </code></pre>
  <p>Any fix would be appreciated. Or If you can tell why it was working earlier just 2 days ago and not now.</p>