parse first X rows / while predicate matches only

[wizzard0]

Feature Proposal

add "while" predicate and/or a "limit" option to get e.g. first 100 rows or "while rows match predicate"

Feature Use Case

exploring/previewing huge files, searching files, auto-detecting column separators

of course, we can just skip lines after parsing, but this wastes CPU and user time :/

[shellscape]

In the data stream event, you can call .end() after N rows have been collected. Any feature added would do the same.

[wizzard0]

oh, I see, it was the underlying Readable that did not close properly, calling .end() on csv-parser connected to regular fs.ReadStream does indeed stop reading. Sorry for bothering then :/

To anybody who might run into a similar issue: tracing events via monkey-patching EventEmitter.prototype.emit and setting highWatermark to something like 4 bytes helps.