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    A rate limiter for Node.js streams.

    API usage

    This module exports two classes, Throttle and ThrottleGroup.

    Throttle creates a single throttled stream, based on stream.Transform. It accepts an opts parameter with the following keys:

    • opts.rate is the throttling rate, in bytes per second.
    • opts.chunksize (optional) is the maximum chunk size into which larger writes are decomposed; the default is opts.rate/10.

    The opts object may also contain options to be passed to the stream.Transform constructor.

    For example, the following code throttles stdin to stdout at 10 bytes per second:

    process.stdin.pipe(new Throttle({rate: 10})).pipe(process.stdout)

    ThrottleGroup allows the creation of a group of streams whose aggregate bandwidth is throttled. The constructor accepts the same opts argument as for Throttle. Call throttle on a ThrottleGroup object to create a new throttled stream belonging to the group.

    For example, the following code creates two HTTP connections to, and throttles their aggregate (downstream) bandwidth to 10 KB/s:

    var addr = { host: '', port: 80 };
    var tg = new ThrottleGroup({rate: 10240});
    var conn1 = net.createConnection(addr),
        conn2 = net.createConnection(addr);
    var thr1 = conn1.pipe(tg.throttle()),
        thr2 = conn2.pipe(tg.throttle());
    // Reads from thr1 and thr2 are throttled to 10 KB/s in aggregate

    Command line usage

    This package installs a throttleproxy binary which implements a command-line utility for throttling connections. Run throttleproxy -h for instructions.


    Feel free to open an issue or send a pull request.


    BSD-style. See the LICENSE file.


    Copyright © 2013 Tiago Quelhas. Contact me at <>.


    npm i stream-throttle

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