npm run alias with autocomplete

.bashrc

alias nr="npm run"

_npm_scripts() {
    # check package.json file in current directory
    if [ ! -f ./package.json ]; then
        return
    fi

    local scripts="$(node -e 'const { scripts } = require(`./package.json`); if (!scripts) process.exit(); let a = Object.entries(scripts); for (let s in scripts) { console.log(s); }' | grep -E ^$2)"
    local -a toks
    local tmp

    if [ -z "$scripts" ]; then
        return;
    fi

    while read -r tmp; do
        toks+=( "$tmp" )
    done <<< "$scripts"

    if [[ ${#toks[@]} -ne 0 ]]; then
        COMPREPLY+=( "${toks[@]}" )
    fi
}

complete -F _npm_scripts nr