Modern SPAs without bundlers, CDNs, or NodeJS

Kofi Gumbs

I typically start new front-end prototypes with a single HTML file that I view using a file:// URL. I enjoy this practice of incrementally growing my projects, so I’ll keep working in that single file for as long as I can. Once it becomes unwieldy, I’ll split out the CSS and JavaScript into dedicated files. Then when manual DOM manipulation gets too complex, I’ll reach for a front-end framework. Until recently though, I wasn’t sure how to make this step feel incremental. Most framework installations recommend npm install, which means my project will now depend on NodeJS. Some frameworks have a hosted CDN option, but I’m similarly uncomfortable accepting that infrastructural dependency. Ideally, I’d just grab the framework files, import them from my JavaScript, and then carry on with my file:// URL.

Well, creating that ideal setup was easier than I expected. My first key discovery was the <script type=importmap> element. Import maps let you write JavaScript modules that depend on named packages without using a bundler. The end result is a SPA that feels modern and standard, but without the need for a compilation step:

<!DOCTYPE html>
<script type=importmap>
    "imports": {
      "solid-js": "/node_modules/solid-js/dist/solid.js",
      "solid-js/html": "/node_modules/solid-js/html/dist/html.js",
      "solid-js/web": "/node_modules/solid-js/web/dist/web.js"
<script type=module>
  // standard import declarations thanks to the import map above
  import html from 'solid-js/html'
  import { render } from 'solid-js/web'

  const HelloWorld = () => {
    // tagged template literals feel close enough to JSX (the defacto standard)
    return html`<div>Hello World!</div>`

  render(HelloWorld, document.getElementById('app'))
<main id=app></main>

That’s almost all of it. This HTML file can be interpreted by most modern browsers, but it references files in /node_modules/solid-js which must be installed. I could do this with npm install, but it’s surprisingly straightforward to download the package directly:

download-package() {
  set -eo pipefail
  local PACKAGE_NAME=$1

  # download the tarball from NPM's registry
  mkdir -p "node_modules/$PACKAGE_NAME"
  curl "$PACKAGE_NAME/-/$PACKAGE_FILE" > "node_modules/$PACKAGE_FILE"

  # verify the tarball's SHA512 checksum
  local PACKAGE_SHA=`shasum -b -a 512 "node_modules/$PACKAGE_FILE" | awk '{ print $1 }' | xxd -r -p | base64`

  # uncompress the package into a directory matching its name
  gunzip -dc "node_modules/$PACKAGE_FILE" | tar -xf - --strip-components 1 -C "node_modules/$PACKAGE_NAME"

# install by manually providing metadata from
download-package solid-js 1.6.6 "5x33mEbPI8QLuywvFjQP4krjWDr8xiYFgZx9KCBH7b0ZzypQCHaUubob7bK6i+1u6nhaAqhWtvXS587Kb8DShA=="

That’s all of it: my bundler-free setup for writing modern JavaScript apps. When I need to add a dependency, I invoke download-package and then declare it in the import map. I like this setup because it feels like I’m only using the bits of the NodeJS ecosystem that I need right now. Later in the project, I could opt into more of what NodeJS has to offer, but it’s neat that I’m not forced into it just to use a UI framework.