Class: Synthra::Output::NdjsonFormatter

Inherits:
Object
  • Object
show all
Defined in:
lib/synthra/output/ndjson_formatter.rb

Overview

NDJSON (newline-delimited JSON) formatter

Instance Method Summary collapse

Instance Method Details

#format_many(records) ⇒ String

Format records to NDJSON string

Parameters:

  • records (Array<Hash>) —

    the records

Returns:

  • (String) —

    NDJSON string



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# File 'lib/synthra/output/ndjson_formatter.rb', line 28

def format_many(records)
  # Append into one buffer instead of allocating an N-element intermediate array of strings.
  # Identical output to map.join("\n") (no trailing newline). For true O(1) memory, stream
  # to an IO with #format_stream instead of materialising the whole string.
  buffer = +""
  records.each_with_index do |record, i|
    buffer << "\n" if i.positive?
    buffer << JSON.generate(record)
  end
  buffer
end

#format_stream(stream, io: $stdout) ⇒ void

This method returns an undefined value.

Format a stream to NDJSON

Parameters:

  • stream (Enumerator) —

    the record stream

  • io (IO) (defaults to: $stdout) —

    output IO object



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# File 'lib/synthra/output/ndjson_formatter.rb', line 15

def format_stream(stream, io: $stdout)
  stream.each do |record|
    io.puts JSON.generate(record)
    io.flush if io.respond_to?(:flush)
  end
end

#write_to_file(stream, path) ⇒ void

This method returns an undefined value.

Write to file

Parameters:

  • stream (Enumerator) —

    the record stream

  • path (String) —

    file path



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# File 'lib/synthra/output/ndjson_formatter.rb', line 47

def write_to_file(stream, path)
  File.open(path, "w") do |file|
    format_stream(stream, io: file)
  end
end