json-text-sequence

Parse and generate JSON text sequences as defined in draft-ietf-json-text-sequence.

JSON text sequences are nice for unambiguous JSON log files. They are resilient to many forms of damage such as truncation, multiple writers incorrectly configured to write to the same file, corrupted JSON, etc. An example sequence:

␞{"d":"2014-09-22T21:58:35.270Z","value":6}␤
␞{"d":"2014-09-22T21:59:15.117Z","value":12}␤

Where "␞" is the ASCII "Record Separator" character (U+001E), and "␤" is the ASCII "LINE FEED" character (U+000A), otherwise known as "\n".

To parse the format, pipe an input source into a parser stream:

var parser = require('json-text-sequence').parser;
var fs = require('fs');

var p = new parser()
  .on('json', function(obj) {
    console.log('JSON:', obj);
  })
  .on('truncated', function(buf) {
    console.log('Truncated:', buf);
  })
  .on('invalid', function(buf) {
    console.log('Invalid:', buf);
  })
  .on('finish', function() {
    console.log('DONE');
  });

fs.createReadStream('example.log').pipe(p);

To generate the format, create a generator, pipe its output somewhere interesting, then write objects to the generator:

var generator = require('json-text-sequence').generator;
var fs = require('fs');

var g = new generator();
g.pipe(fs.createWriteStream('example.log'));

g.write({
  d: new Date(),
  count: 0
});