Async/await is pure syntactic sugar. Look at python 3.0 era coroutines that were iterator/generator based as an example of async coding without special keyword

Async/await is pure syntactic sugar. Look at python 3.0 era coroutines that were iterator/generator based as an example of async coding without special keywords. JS did not need those keywords to enable coroutines and async coding. People were already making their own promises, coroutines, etc. long before the new keywords were added.