package.json

{
    "scripts": {
        "pretest": "exit 1",
        "test": "exit 1",
        "posttest": "echo post-test"
    }
}

yarn

#!/bin/bash

set -o nounset -o noclobber -o pipefail -e

get_script() {
    if [[ $1 == "run" ]]; then
        shift
    fi
    echo "$1"
    shift    
}

get_cmd() {
    local cmd=$1
    <./package.json jq -r ".scripts[\"$cmd\"] | select (.!=null)"
}

run_cmd() {
    local cmd=$1
    echo "\$ $cmd"
    sh -c "$cmd"
}

run_prepost() {
    local prefixed
    prefixed=$1
    local cmd
    cmd=$(get_cmd "$prefixed")
    if [[ -n "$cmd" ]]; then
        run_cmd "$cmd"
    fi
}

main() {
    local script
    script=$(get_script "$@")

    local cmd
    cmd=$(get_cmd "$script")
    if [[ -z "$cmd" ]]; then
        echo "error Command \"$script\" not found." | grep --color 'error'
        exit 1
    fi

    run_prepost "pre$script"
    run_cmd "$cmd" "$@"
    run_prepost "post$script"
}

main "$@"