Natural Preference for Minification


    0.1.6 • Public • Published


    cargo-cp-artifact is a small command line utility for parsing cargo metadata output and copying a compiler artifact to a desired location.


    npm install -g cargo-cp-artifact


    cargo-cp-artifact --artifact artifact-kind crate-name output-file -- wrapped-command

    cargo-cp-artifact accepts a list of crate name and artifact kind to output file mappings and a command to wrap.cargo-cp-artifact will read stdout of the wrapped command and parse it as cargo metadata. Compiler artifacts that match arguments provided will be copied to the target destination.

    When wrapping a cargo command, it is necessary to include a json format to --message-format.


    Multiple arguments are allowed to copy multiple build artifacts.


    Alias: -a

    Followed by three arguments: artifact-kind crate-name output-file


    Alias: -n

    Followed by two arguments: artifact-kind output-file

    The crate name will be read from the npm_package_name environment variable. If the package name includes a namespace (@namespace/package), the namespace will be removed when matching the crate name (package).

    Artifact Kind

    Valid artifact kinds are bin, cdylib, and dylib. They may be abbreviated as b, c, and d respectively.

    For example, -ac is the equivalent of --artifact cdylib.


    Wrapping cargo

    cargo-cp-artifact -a cdylib my-crate lib/index.node -- cargo build --message-format=json-render-diagnostics

    Parsing a file

    cargo-cp-artifact -a cdylib my-crate lib/index.node -- cat build-output.txt

    npm script


        "name": "my-crate",
        "scripts": {
            "build": "cargo-cp-artifact -nc lib/index.node -- cargo build --message-format=json-render-diagnostics"
    npm run build
    # Additional arguments may be passed
    npm run build -- --feature=serde

    Why does this exist?

    At the time of writing, cargo does not include a configuration for outputting a library or binary to a specified location. An --out-dir option exists on nightly, but does not allow specifying the name of the file.

    It surprisingly difficult to reliably find the location of a cargo compiler artifact. It is impacted by many parameters, including:

    • Build profile
    • Target, default or specified
    • Crate name and name transforms

    However, cargo can emit metadata on stdout while continuing to provide human readable diagnostics on stderr. The metadata may be parsed to more easily and reliably find the location of compiler artifacts.

    cargo-cp-artifact chooses to wrap a command as a child process instead of reading stdin for two reasons:

    1. Removes the need for -o pipefile when integrating with build tooling which may need to be platform agnostic.
    2. Allows additional arguments to be provided when used in an npm script.


    npm i cargo-cp-artifact

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    • dherman
    • kjv