Note she's only comparing it with TraceMonkey (which is now gone from SpiderMonkey) and the initial V8 compiler (i.e., not the optimising Crankshaft compiler).

Note she's only comparing it with TraceMonkey (which is now gone from SpiderMonkey) and the initial V8 compiler (i.e., not the optimising Crankshaft compiler). This makes competing much easier. It's about the timespan I'd have expected — Carakan (the second latest in-browser JS VM; Chakra is the latest, but relatively little is known about it) was essentially feature complete and competitive on perf after nine months of development (with 3.5 developers, and an increasing number of QA from 0.5 up to 2). Carakan's big thing was finding and fixing ever more obscure bugs (especially in the compiler), taking almost the same time again.