Declare TypeScript SDK path in VSCode settings.

[lijunle]

As of VSCode 1.6.0, it use 2.x as default. This project still uses 1.8. If not declare the path explicitly, VSCode will prompt to choose version every time.

[msftclas]

Hi @lijunle, I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!

It looks like you're a Microsoft contributor (Junle Li). If you're full-time, we DON'T require a Contribution License Agreement. If you are a vendor, please DO sign the electronic Contribution License Agreement. It will take 2 minutes and there's no faxing! https://cla.microsoft.com.

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