Get the latest version of npm or jsr packages (augment Deno's lack of `@latest` tag)

pkg_latest.sh

#!/usr/bin/env bash

# pkg-latest: Get the latest version of npm or jsr packages
# Inspired by: https://github.com/sigmaSd/pkg-latest (written in Rust)
# Requires: curl, jq

# Usage: pkg_latest <npm:package|jsr:package>
# Example: pkg_latest npm:preact
# Example: pkg_latest jsr:@fresh/init

# Usage as a function: deno install $(pkg_latest npm:preact)

pkg_latest() {
    local input="$1"

    # Check if argument is provided
    if [[ -z "$input" ]]; then
        echo "Usage: pkg_latest <npm:package|jsr:package>" >&2
        return 1
    fi

    # Handle npm: prefix
    if [[ "$input" =~ ^npm:(.+)$ ]]; then
        local package_name="${BASH_REMATCH[1]}"
        local url="https://registry.npmjs.org/${package_name}"

        local response
        if ! response=$(curl -fsSL -H "Accept: application/json" "$url" 2>&1); then
            echo "Error: Failed to get npm version for ${package_name}: ${response}" >&2
            return 1
        fi

        local version
        if ! version=$(echo "$response" | jq -r '.["dist-tags"].latest' 2>&1); then
            echo "Error: Failed to parse npm response for ${package_name}" >&2
            return 1
        fi

        if [[ "$version" == "null" || -z "$version" ]]; then
            echo "Error: No latest version found for ${package_name}" >&2
            return 1
        fi

        echo "npm:${package_name}@${version}"

    # Handle jsr: prefix
    elif [[ "$input" =~ ^jsr:(.+)$ ]]; then
        local package_name="${BASH_REMATCH[1]}"
        local url="https://jsr.io/${package_name}/meta.json"

        local response
        if ! response=$(curl -fsSL -H "Accept: application/json" "$url" 2>&1); then
            echo "Error: Failed to get jsr version for ${package_name}: ${response}" >&2
            return 1
        fi

        local version
        if ! version=$(echo "$response" | jq -r '.latest' 2>&1); then
            echo "Error: Failed to parse jsr response for ${package_name}" >&2
            return 1
        fi

        if [[ "$version" == "null" || -z "$version" ]]; then
            echo "Error: No latest version found for ${package_name}" >&2
            return 1
        fi

        echo "jsr:${package_name}@${version}"

    else
        echo "Error: Input must start with 'npm:' or 'jsr:'" >&2
        return 1
    fi
}

# If script is executed directly (not sourced), run the function
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    pkg_latest "$@"
fi