git ssb

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var u = require('pull-core')
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var prop = u.prop
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var id   = u.id
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var maybeSink = u.maybeSink
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module.exports = function (pull) {
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  var exports = {}
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  var drain = pull.drain
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  var find =
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  exports.find = function (test, cb) {
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    return maybeSink(function (cb) {
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      var ended = false
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      if(!cb)
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        cb = test, test = id
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      else
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        test = prop(test) || id
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      return drain(function (data) {
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        if(test(data)) {
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          ended = true
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          cb(null, data)
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        return false
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        }
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      }, function (err) {
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        if(ended) return //already called back
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        cb(err === true ? null : err, null)
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      })
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    }, cb)
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  }
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  var reduce = exports.reduce =
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  function (reduce, acc, cb) {
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    return maybeSink(function (cb) {
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      return drain(function (data) {
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        acc = reduce(acc, data)
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      }, function (err) {
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        cb(err, acc)
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      })
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    }, cb)
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  }
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  var collect = exports.collect = exports.writeArray =
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  function (cb) {
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    return reduce(function (arr, item) {
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      arr.push(item)
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      return arr
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    }, [], cb)
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  }
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  var concat = exports.concat =
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  function (cb) {
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    return reduce(function (a, b) {
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      return a + b
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    }, '', cb)
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  }
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  return exports
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}
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