Add config to explicitly set 'usingTypeScript'

[olsonpm]

Goals

I'm building an editor and have a file "initial-code.ts" which I'm importing as text, not as typescript. I want to keep its .ts extension for syntax highlighting when I edit it.

during next build this file causes next to assume my project uses typescript - breaking when an imported dependency in that file doesn't exist in my project.

by adding a config 'usingTypeScript' I can tell next to skip unwanted typescript processes

Non-Goals

No response

Background

I didn't see any discourse when checking github discussions and issues for the initial error I received "Linting and checking validity of types". Also googled for a while to learn what was going on.

I looked at next.js's code and didn't see a sensible way to get around its assumption that my project used typescript. I understand wanting to keep things easy for folk and auto-detecting TS - but believe a config should exist to be explicit.

Proposal

Here is my initial implementation

olsonpm@43b7121?w=1

it adds a new config 'usingTypeScript' which defaults to 'auto' preserving existing behavior. By setting it to true or false, it skips the intent step and responds appropriately.