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Your tsconfig.json is probably not valid anymore. TypeScript 7 made it official.
TypeScript 7 compiles with a Go-based compiler, so many of the legacy options you’ve been copy-pasting into your tsconfig.json files over the years will cause your builds to fail.
When I upgraded to TS7 I expected a free performance boost, but when I ran my first build I got an error that I’d never seen before. It was caused by a setting I had in my tsconfig.json file that I added in 2019 that I hadn’t given any thought to since.
What Has Been Modified?
TypeScript 7 is an implementation of the TypeScript compiler written in Go. According to Microsoft, full builds will be approximately 8 to 12 times faster than they were using TypeScript 6.0. While the language remains unchanged and the command remains `tsc`, there are several modifications including; increased performance, new default settings, and the elimination of options that were previously deprecated in TypeScript 6.
However, the problem lies within your `tsconfig` file; many developers have carried over habits from years past.
The Defaults That Can Cause Problems
- rootDir: This setting now defaults to the directory containing your `tsconfig.json` file. Therefore, if you have your source…
