streaming functional transformer for couchdb using node

couch-transform.js

var request = require('request').defaults({json: true}),
  transfuse = require('transfuse'),
  JSONStream = require('JSONStream');

function transform(couchdb, funcString, headers) {
  var down = request({url: couchdb + '/_all_docs?include_docs=true'}),
    up = request({url: couchdb + '/_bulk_docs', method: "POST", headers: headers}),
    tr = transfuse(['rows', /./, 'doc'], funcString, JSONStream.stringify("{\"docs\":[\n", "\n,\n", "\n]}\n"));
  down.pipe(tr)
  tr.pipe(up)
}

// transform('http://localhost:5984/cats', 'function(doc, map) { doc.type = "cat"; map(doc) }')

How about converting funcString for me?

function transform(couchdb, func, headers) {
    var funcString = func.toString()
    // ...
}

// transform('http://localhost:5984/cats', function(doc, map) { doc.type = "cat"; map(doc) })

transfuse uses vm.runInNewContext to execute the funcString argument if it is a string. otherwise it just uses the function you pass in

awesome stuff :)

just dont stream large documents cause jsonparse buffers them and mem usage will increase and performance will be slower, more prone to errors, etc

only n00bz store large documents anyway :D

yeah :) but you might be streaming something large into couch :)

also selectors like mikeal suggested really help performance. I only implemented simple dot notation but in the best case scenario you could go from taking 2 seconds to parse npmjs to 0.05.