git ssb

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module.exports = function GroupUntil (check) {
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  let ended = false
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  let queue = []
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  return function (read) {
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    return function (end, cb) {
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      // this means that the upstream is sending an error.
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      if (end) {
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        ended = end
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        return read(ended, cb)
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      }
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      // this means that we read an end before.
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      if (ended) return cb(ended)
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      read(null, function next (end, data) {
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        ended = ended || end
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        if (ended) {
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          if (!queue.length) {
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            return cb(ended)
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          }
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          const _queue = queue
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          queue = []
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          return cb(null, _queue)
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        }
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        if (check(queue, data)) {
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          queue.push(data)
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          read(null, next)
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        } else {
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          const _queue = queue
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          queue = [data]
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          cb(null, _queue)
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        }
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      })
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    }
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  }
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}
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