range-slice-stream

Extract a bunch of ranges from a stream to construct a new stream

Usage

const RangeSliceStream = require('range-slice-stream')

const slicer = new RangeSliceStream()
slicer.end('abcdefghijklmnop')

const out = slicer.slice([
  { start: 1, end: 3 },
  { start: 6, end: 9 }
])

out.pipe(process.stdout)

// Prints 'bcghi'

API

var slicer = new RangeSliceStream([offset[, opts]])

Create a new slicer, which is a writable stream.

If an offset is provided, it is subtracted from all range offsets. This makes it more intuitive to use if the incoming data stream itself starts at an offset into an underlying resource like a file.

opts is passed to the underlying writable stream constructor.

var slice = slicer.slice([{start: <s1>, end: <e1>}, {start: <s2>, end: <e2>},...])

Get a new readable stream that is built by concatenating the data from one or more byte ranges of the data piped into the slicer. Like the Buffer.slice() method, start is inclusive and end is exclusive.

slice() can be called multiple times to generate multiple streams built from different sets of ranges. However, all ranges must be provided in increasing order, both within a given call to slice() and between calls.

Data between ranges is discarded. Once all ranges specified by slice() calls are satisfied, backpressure will be applied to the incoming stream until the next desired range is specified by calling slice() again.

slicer.satisfied

Boolean that is true when all slice() calls have been satisfied and backpressure is applied. In addition, the satisfied event is emitted when slicer.satisfied becomes true.

License

MIT