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Bundler Polyfill issues - Vite

While setting up a new Web3 project from scratch, you might face bundler issues. This can occur because the core packages like eccrypto have dependencies which are not present within the build environment.

To rectify this, the go-to method is to add the missing modules directly into the package, and edit the bundler configuration to use those. Although this approach works, it can significantly increase bundle size, leading to slower load times and a degraded user experience.

Some libraries rely on environment-specific modules that may be available at runtime in the browser even if they are not bundled. Libraries such as Embedded Wallets’ Web3Auth take advantage of this behavior and can function correctly without bundling all modules. However, if you are using a library that does not take advantage of this, you might face issues.

To avoid unnecessary overhead, include only the required polyfills, test functionality, and configure your bundler to ignore unresolved modules rather than including them in the final build.

tip

We recommend that you require certain Node polyfills to be added to your project, while testing each of its functionalities. At the same time, instruct the bundler to ignore the missing modules, and not include them in the build.

In this guide, we provide instructions for adding polyfills in Vite.

Step 1: Install the missing modules​

Check for the missing libraries in your build and included packages, and accordingly polyfill them. For Web3Auth, you just need to polyfill the buffer and process libraries.

npm install --save-dev buffer process

Step 2: Add the polyfills to your project​

Update the index.html file to include the polyfills. As shown in the code snippet below we added the <script> tag to include the polyfills.

<!doctype html>
<html lang="en">
  <head>
    <script type="module">
      import { Buffer } from 'buffer'
      import process from 'process'
      window.Buffer = Buffer
      window.process = process
    </script>
    <meta charset="UTF-8" />
    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  </head>
  <body>
    <div id="root"></div>
    <script type="module" src="/src/main.tsx"></script>
  </body>
</html>

Step 3: Update your vite.config.js​

Next, update the nuxt.config.js file to define the global object.

warning

If you're using any other blockchain library alongside Web3Auth, it's possible that you might need to polyfill more libraries. Typically, the libraries like crypto-browserify, stream-browserify, browserify-zlib, assert, stream-http, https-browserify, os-browserify, url are the ones that might be required, with crypto-browserify and url being the most common polyfills.

/* eslint-disable import/no-extraneous-dependencies */
import react from '@vitejs/plugin-react'
import { defineConfig } from 'vite'

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [react()],
  // alias are only to be added when absolutely necessary, these modules are already present in the browser environment
  // resolve: {
  // alias: {
  // crypto: "crypto-browserify",
  // assert: "assert",
  // http: "stream-http",
  // https: "https-browserify",
  // url: "url",
  // zlib: "browserify-zlib",
  // stream: "stream-browserify",
  // },
  // },
  define: {
    global: 'globalThis',
  },
})
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