Fast, asynchronous, functional reactive stream programming framework with multi‑threading capability based on ES6+.

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  • Scramjet Modules

    A Scramjet module is a simple module that exposes a single function that performs some operations with the stream. The API is designed so that these modules can be easily used on any stream you like without needing to use scramjet.

    For a quick example please see the signicode/scramjet-module repository.

    Using scramjet modules

    Using a scramjet module is fairly simple, first install it as a dependency:

    $ npm i -s scramjet-module

    Next simply use it in your code:

        DataStream.from('scramjet-module/hello-read') // Loads and sources the stream from the `hello-read`
                                                      // scramjet module of `scramjet-module` package
            .use('scramjet-module/hello-transform')   // This loads and uses `hello-transform` from the same package.

    Scramjet modules are resolved automatically in relation to the calling file, just like node.js require method.

    Incidentally scramjet is not needed as a peer to use a scramjet module. The API is thought in a way so it will be fully interoperable with any stream you like, so you can simply use them with another stream and they always return a standard Node.js readable stream. This means you can use it with any stream - maybe gulp?

    import {helloRead} from 'scramjet-module';

    Another option

    Writing a sample read module

    Here's how a minimal read module may look like:

    import {StringStream, createReadModule} from "scramjet";
    export default const ndjsonStream = createReadModule(
        (file) => StringStream
            .parse(x => JSON.parse(x))

    Or in commonjs:

    const {StringStream, createReadModule} = require("scramjet");
    module.exports = createReadModule(
        (file) => StringStream
            .parse(x => JSON.parse(x))

    Here's how it would be used:

    import readFile from "scramjet-read-ndjson";
        .each(x => console.log(

    Or even easier with DataStream.from:

        .each(x => console.log(;

    Usage with CLI

    Scramjet provides a simple CLI mechanism that allows chaining number of modules one after another without writing any code.

    $ npm i -g scramjet-cli
    $ scramjet -i 'scramjet-hello/read' 'scramjet-hello/transform1' [...] -o './file'

    You can see more information in scramjet-cli repo.

    A sample transform module

    Here's how a minimal transform module may look like:

    import {StringStream, createTransformModule} from "scramjet";
    export default const ndjsonStream = createTransformModule(
        (stream, hello = "Hello, {}!") => stream
            .stringify(name => hello.replace('{}', name.toString()))

    Or in commonjs:

    const {StringStream, createTransformModule} = require("scramjet");
    module.exports = createTransformModule(
        (stream, hello = "Hello, {}!") => stream
            .stringify(name => hello.replace('{}', name.toString()))

    Publishing scramjet modules

    In general scramjet modules can be published as standard npmjs packages.

    If your package contains multiple modules, you may want to set meaningful names so that when your users require the package they'll know what they are referring to:

    import commonlogTransform from "scramjet-common-log/transform";
    import svgRead from "scramjet-csv/read";