Description

This PR fixes the yarn clean which has been broken since #327.

TypeScript 3.4 introduces a new flag called --incremental which tells TypeScript to save information about the project graph from the last compilation. The next time TypeScript is invoked with --incremental, it will use that information to detect the least costly way to type-check and emit changes to your project.

TypeScript 3.4 introduced --incremental and it is set to true by default when --composite is true which is the our case.

Therefore,tsconfig.tsbuildinfo is generated and it causes the yarn bundle && yarn clean && yarn bundle to fail.

TypeScript will look for a file called .tsbuildinfo in the output directory (./lib). If ./lib/.tsbuildinfo doesn’t exist, it’ll be generated. But if it does, tsc will try to use that file to incrementally type-check and update our output files.

To fix the issue, this PR removes the tsconfig.tsbuildinfo files when yarn clean.
Also, it sets the compiler option incremental value as true explicitly which is already true implicitly.

Motivation and Context

How has this been tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• Add tests to cover changes as needed.
• Update documentation as needed.