I didn’t look at your code, because your description of your setup has a lot of red flags. Do you see how the versions you report are different from what’s in package.json? You could have all kinds of weird errors. Also, I don’t even know how Typescript 2.0x handles async/await.
Install the current Node LTS, and the most recent version of Ionic 3. Then read the Ionic changelog to determine which version of Typescript to install. Make sure your package.json is consistent with the changelog.