Specialized fast async file writer

ported by JS steno

Celer means fast in Latin.


Celer makes writing to the same file often/concurrently fast and safe.

  • ⚡ pretty fast under specific situation (see benchmark)
  • Included the Benchmark/Test in a flutter way


in normal situation like single-time write, it rather be slower than the normal dart:io method

Getting started

nothing needs to be started.


/// data setup codes
final dir = await Directory.systemTemp.createTemp('celer-test-');
final celerFile = File(p.join(dir.path, 'celer.txt'));
final data = String.fromCharCodes(List.filled(1024, 'x'.codeUnitAt(0)));
final dataset = List.generate(1000, (index) => data);

/// usage
/// init celer writer
final celer = CelerWriter(celerFile.path);

/// write
/// Repeatedly write to the same file
await Future.wait(dataset.map((e) => celer.write(e)));

Additional information

In benchmark, We measured and compared the time when writing kb,mb-sized text 1000 times to the same file.

Write 1KB data to the same file x 1000
celer(Runtime): 5820.627906976744 us.
io(Runtime): 115485.27777777778 us.
Write 1MB data to the same file x 1000
celer(Runtime): 22048.14285714286 us.
io(Runtime): 7442817.0 us.

You can run benchmark yourself by

dart run benchmark/tester.dart


It can be measured differently on your computer.


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