The article is measuring full project build performance. That includes type-checking and compilation.
Maybe the `tsc` type-checker was already fast (so we only get some speed improvements in `tsgo`), or the `tsc` compiler was not that fast (so we get a lot of speed improvements in `tsgo`)?
*Update:* There was a performance regression in incremental type-checking between `tsgo` preview 20251209 and 20251211 [1]. But `deno` is using `tsgo` 0.1.11 which was already released last week (before this regression). So, does not seem to influence the type-checking times here.
Maybe the `tsc` type-checker was already fast (so we only get some speed improvements in `tsgo`), or the `tsc` compiler was not that fast (so we get a lot of speed improvements in `tsgo`)?
*Update:* There was a performance regression in incremental type-checking between `tsgo` preview 20251209 and 20251211 [1]. But `deno` is using `tsgo` 0.1.11 which was already released last week (before this regression). So, does not seem to influence the type-checking times here.
[1] https://github.com/microsoft/typescript-go/issues/2341 [2] https://github.com/denoland/deno/blob/v2.6.0/cli/tsc/go/tsgo...