elavoie/pull-stubborn

Keeps resubmitting inputs to transformer until the corresponding outputs test successfully.

Keeps resubmitting inputs to transformer until the corresponding outputs test successfully. May not preserve the input order.

Expectation on Transformer:

• Outputs a single value per input

Example Usage

var pull = require('pull-stream')
var stubborn = require('pull-stubborn')

pull(
  pull.count(3),
  stubborn(
    pull.map(function (x) { 
      return { 
        status: Math.random() * 10,
        input: x,
        result: x*x
      } 
    }),
    function tester (x, cb) {
      var success = x.status >= 5 // 50% chance of success
      if (success) 
        cb(true, x.result) // Return result
      else 
        cb(false, x.input) // Resubmit input
    }
  ),
  pull.collect(function (err, arr) {
    if (err) return console.error(err)
    arr.sort()       // Results may be out of order
    console.log(arr) // Prints 0,1,4,9
  })
)

stubborn(transformer/duplex, tester(x, cb)) returns another transformer/duplex

cb has the following signature cb(success, value). If success===true then value is passed downstream. Otherwise, value is submitted to transformer/duplex again as input. Each case may use a different value.