The point the parent is making is that the boring normal code in NodeJS is not slow, at least not as presented in the article. The bottleneck is probably somewhere else. Allocation is usually not slow in a garbage collected language. Deallocation can be, but that is usually easy to check (for example with the --trace-gc flag, or running with profiling enabled and checking the results with chrome devtools). It would have been nice if they shared such analysis.

With the limited information provided in the article, there are other points that I would check before going as far as writing a module in another language. For example

> records.push({

They are collecting all the parsed rows in a single array. This is going to consume memory proportional to the size of the file, potentially in the same order of magnitude (depends on how much information is being collected and how much discarded).