Create throttled through stream
Inspired by node-throttle module, but acts as a through stream and splits input chunks if required to maintain target speed as close as possible.
$ npm install shaper
'Slow cat' example:
var shape = require'shaper';processstdinpipeshape10pipeprocessstdout end: false ;processstdinresume;
$ time echo "this is 58-chars long string (including trailing newline)" | node examples/slowcat.jsthis is 58-chars long string (including trailing newline)real 0m5.912suser 0m0.056ssys 0m0.012s
var shaper = require'shaper';var shapeStream = shaperbyteRate chunkRate lowWatermark highWatermark
byteRate - targeted speed in bytes per second
chunkRate - (default is 10) - output chunk rate. If target speed is 20000 bytes per second and chunk rate is 100, you'll have 100 chunks per second stream, each 200 bytes in size (on average). Note that if input stream is slower then target, chunks are sent immideately at input rate, wich could be higher than target chunk rate. If input is 1000 chunks per second, each 10 bytes
shape(20000, 500) should give same 1000 chunk per second x 10 bytes stream.
lowWatermark - emit
drain event if buffer size is less than this paremeter. Default to 0.
highWatermark - size when buffer is considered full. Default to 0.