level-objectify

Compile the contents of a leveldb read stream into an object and create a patch for changes as a batch update.

Example

level = require('level-test')()
objectify = require('../')

db = level 'level-objectify-test', {valueEncoding: 'json'}

var c1 = {
  person: {
    gaius: {name: 'Gaius Baltar'},
    six: {name: 'Six'}
  }
}

// {depth: 1} = use the first layer of keys as a prefix to their children
var batch = objectify({depth: 1}).computeBatch({}, c1)
// returns a valid leveldb batch of operations.
// [
//   { key: 'personÿgaius', type: 'put', value: { name: 'Gaius Baltar' } },
//   { key: 'personÿsix', type: 'put', value: { name: 'Six' } }
// ]

db.batch(batch)

// with data already in the db, the contents can be objectified
db.readStream().pipe(objectify({depth: 1}).compile(function (err, result) {
  if (err) return console.log('problem', err)

  // `result` matches the object we started with!
  assert.deepEqual(c1, result)
  // see the tests for more examples.
}))

Usage

var obj = objectify(opts={})

options

• opts.depth = 0 the depth of key that should be used as a prefix for each property
• opts.separator = '\xff' the string to use to separate sections of the prefix.

Methods

obj.compile(callback(err, result))

Returns a writable stream that expects data in the format {key: ..., value: ...} (like the data emitted by level.readStream()). When the stream ends, callback is called with any error and the compiled result.

obj.computeBatch(prev, next)

Returns a batch operations array (compatible with leveldb) that will patch the database in the state prev to match the state of next. Behind the scenes, this method just calls obj.convertPatch(obj.computePatch(prev, next)).

obj.computePatch(prev, next)

Exports computePatch() from patcher.

Contributing

Please make any changes to the .coffee source files and npm build before sending a pull request.

License

MIT