Each experiment ships its code, the exact command that produced the numbers, and the raw results with the machine they ran on.
2 experimentsData generated Nov 11, 2026
−57%check time with TypeScript 7 after the fix
Yes. Inferring the event name from the generic parameter cut check time by about 40% with TypeScript 6 and by about 65% with TypeScript 7, with the same type safety. Narrowing include to src also stopped TypeScript from reading a generated file the app never imports.
Read the experimentOpened October 2026. Latest run: Apple M3 Pro, 12 cores, 36 GB, Node.js 22.23.3, Nov 9, 2026. 2 machines in total.
3.5×faster check of type-fest sources, TypeScript 7 vs 6
On an Apple M3 Pro (12 cores), TypeScript 7.0.2 checked the type-fest sources 3.5× faster than TypeScript 6.0.3 (0.484 s vs 1.67 s): 2.6× comes from the native compiler alone (single-threaded) and 1.3× from parallel checking. On the full suite with type tests, TypeScript 6 stops at Node.js's default heap limit (4.0 GiB); with a 16 GiB heap it finishes in 74.6 s, against 14.1 s for TypeScript 7 (5.3× faster), but TypeScript 7 peaks higher in memory (11.6 GiB RSS vs 10.4 GiB). Stays open until a second machine is measured with the same protocol.
Read the experimentLatest run: Apple M3 Pro, 12 cores, 36 GB, Node.js 22.23.3, Nov 11, 2026. 2 machines in total.
Six rules that make a number worth publishing. The lab repository has the scripts.
Compiler versions, external commits and machine context are recorded with every result.
Three runs of tsc with extended diagnostics per condition, median reported with the range.
A fix changes a single thing and keeps the same type safety.
A safety file lists usages that must still fail to compile. The run stops if one passes.
Confirmed, rejected or open. Negative results are published too.
Compare conditions on the same machine only. Counters may differ across compilers.