60 lines
1.3 KiB
JavaScript
60 lines
1.3 KiB
JavaScript
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//filter will reemit the data if cb(err,pass) pass is truthy
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// reduce is more tricky
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// maybe we want to group the reductions or emit progress updates occasionally
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// the most basic reduce just emits one 'data' event after it has recieved 'end'
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var through = require('through')
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var Decoder = require('string_decoder').StringDecoder
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module.exports = split
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//TODO pass in a function to map across the lines.
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function split (matcher, mapper) {
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var decoder = new Decoder()
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var soFar = ''
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if('function' === typeof matcher)
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mapper = matcher, matcher = null
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if (!matcher)
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matcher = /\r?\n/
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function emit(stream, piece) {
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if(mapper) {
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try {
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piece = mapper(piece)
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}
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catch (err) {
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return stream.emit('error', err)
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}
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if('undefined' !== typeof piece)
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stream.queue(piece)
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}
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else
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stream.queue(piece)
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}
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function next (stream, buffer) {
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var pieces = (soFar + buffer).split(matcher)
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soFar = pieces.pop()
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for (var i = 0; i < pieces.length; i++) {
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var piece = pieces[i]
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emit(stream, piece)
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}
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}
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return through(function (b) {
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next(this, decoder.write(b))
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},
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function () {
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if(decoder.end)
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next(this, decoder.end())
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if(soFar != null)
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emit(this, soFar)
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this.queue(null)
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})
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}
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