Install npm dependencies that run directly in the browser. No Browserify, Webpack or import maps required.

Fred K. Schott ed4ff517e0 0.3.0 4 months ago
assets 5c01c31b29 add a babel transform plugin 4 months ago
src 2f9b68028e add "optimize" option 4 months ago
.gitignore c74a408d8a initial commit 4 months ago
.prettierrc c74a408d8a initial commit 4 months ago
LICENSE e56fa8d026 Create LICENSE 4 months ago 2304bdb7cb some interface cleanup 4 months ago
package-lock.json ed4ff517e0 0.3.0 4 months ago
package.json ed4ff517e0 0.3.0 4 months ago
tsconfig.json c74a408d8a initial commit 4 months ago


@pika/web • Install npm dependencies that run directly in the browser. No Browserify, Webpack or import maps required.


npm on Dec 6, 2018 - *"JavaScript in 2018 is somewhat notorious for requiring a lot of tooling to get going, which is quite a reversal from the situation in 2014... All of our survey respondents would like to see less tooling [and] less configuration required to get started."*

@pika/web brings that nostalgic, 2014 simplicity to 2019 web development:

  • Simple 💪 No bundlers required. Load modern, ESM packages natively in the browser.
  • Flexible 🧘‍♂️ Handles dependency trees of any size, even ones that includes legacy Common.js packages.
  • HTTP/2 Optimized ⚡️ No more huge, cache-busting bundles. Browsers only download deps when they change.


npm install --save-dev @pika/web
yarn add --dev @pika/web
# 1. Run @pika/web in your project:
$ npx @pika/web

# 2. Replace all NPM package imports in your web app with web-native URLs:
- import { createElement, Component } from "preact";
- import htm from "htm";
+ import { createElement, Component } from "/web_modules/preact.js";
+ import htm from "/web_modules/htm.js";

# 3. Run that file directly in the browser and see the magic! 
✨ ~(‾▿‾~)(~‾▿‾)~ ✨

# (Optional) If you already use Babel to build your application, skip "Step 2" and let our plugin rewrite your imports automatically:
echo '{"plugins": [["@pika/web/assets/babel-plugin.js"]]}' > .babelrc

# (Optional) Add a package.json "prepare" script to run @pika/web on every npm install:
{"scripts": {"prepare": "pika-web"}}

By default, @pika/web will install all package.json dependencies with an ES "module" entrypoint to the web_modules/ directory. @pika/web is able to handle any legacy Common.js/Node.js transitive dependencies in your dependency tree, however the top-level dependencies (the ones that you import directly) must have a "module" entrypoint.

┳┻| _
┻┳| •.•) 💬 "Tip: Use to find modern, web-ready packages on npm :)"


When @pika/web installs your dependencies, it bundles each package into a single ESM JavaScript file. Shared chunks are created for any transitive dependencies shared between them, if they exist. Example: If @pika/web installs 10 npm packages into web_modules/, you can expect 10 JavaScript files and maybe a few additional shared chunks.

Max Jung's post on "The Right Way to Bundle Your Assets for Faster Sites over HTTP/2" is the best study on HTTP/2 performance & bundling that we could find online. @pika/web's installation most closely matches the study's moderate, "50 file" bundling strategy. Jung's post found that for HTTP/2, "differences among concatenation levels below 1000 small files were negligible."

More testing is obviously needed, but at this early stage we feel confident extrapolating the following: When served with HTTP/2, @pika/web installations perform better in production than single "vendor" JavaScript bundles and most custom dependency bundling strategies due to the comparable load performance + more efficient cache usage.


Pika's mission is to make modern JavaScript more accessible by making it easier to find, publish, install, and use modern packages on npm. You can learn more the Pika project at


package.json Options

Note: All package.json options are scoped under the "@pika/web" property.

  • "webDependencies": You can define an optional whitelist of "webDependencies" in your package.json manifest. This is useful if your entire "dependencies" object is too large or contains unrelated, server-only packages that may break @pika/web.
  "dependencies": {
    "htm": "^1.0.0",
    "preact": "^8.0.0",
    /* A mix of other server and frontend dependencies */
  "@pika/web": {"webDependencies": ["htm", "preact"]},

CLI Options

  • --dest: Specify destination directory (default: web_modules/).
  • --clean: Clear out the destination directory before install.
  • --optimize: Minify installed dependencies.
  • --strict: Only install pure ESM dependency trees. Great for purists, or anyone who doesn't want to deal with transitive Common.js and Node.js-only dependencies.

Special Thanks: Rollup

@pika/web is powered internally by Rollup. We believe that bundlers shouldn't be a requirement for modern web development, but none of this would be possible without the awesome work done by Rollup contributors. If you use and enjoy our software, consider contributing back to Rollup on Open Collective.