They are comparing Javascript JIT to Javascript AOT, to avoid the issue of language design. "The fastest contemporary JavaScript implementations use JIT compil

They are comparing Javascript JIT to Javascript AOT, to avoid the issue of language design. "The fastest contemporary JavaScript implementations use JIT compilers [27]. ... However, JIT compilers may not be desirable or simply not available in some contexts, for instance if programs are to be executed on platforms with too limited resources or if the architecture forbids dynamic code generation. Ahead of time (AoT) compilers offer a response to these situations. Hopc [25] is an AoT JavaScript-to-C compiler. Its performance is often in the same range as that of the fastest JIT compilers but its impossibility to adapt the code executed at runtime seems a handicap for some patterns and benchmarks [27]." In the context of JS it's reasonable to think that JIT may have an advantage, as the language is difficult to statically analyse.