non-digested assets in webpack (e.g. non-stupid-digest-assets for webpacker)

webpacker-environment.js

// Didn't find anything on google for this so I wrote my own. Use as a starting point if you have a similar problem.
// Please write comments if there is a better way to do this (or solve the same problem in another way) in webpack.

// Contents of config/webpack/environment.js:

const { environment } = require('@rails/webpacker')

// Generate undigested assets for use in embedded javascript, emails, etc.
// We previously used non-stupid-digest-assets for this.

environment.plugins.set("UndigestedAssets", function() {
  this.plugin("emit", function(compilation, compileCallback) {
    var fs = require("fs")
    var path = require("path")
    var manifest = JSON.parse(compilation.assets["manifest.json"].source())

    for(var sourceFile in manifest) {
      var targetFile = manifest[sourceFile]
      outputPath = "/" + path.basename(compilation.options.output.path) + "/"
      assetKey = targetFile.replace(outputPath, "")

      // Make output paths for undigested files the same as sprockets so that old links still work.
      outputPath = sourceFile.replace("_/assets/images/", "")
      outputPath = outputPath.replace("_/assets/fonts/", "")
      outputPath = outputPath.replace("_/assets/", "")

      // When an error happens in development, all assets are not compiled, we
      // need to handle that so we don't crash webpack :)
      if(compilation.assets[assetKey]) {
        compilation.assets[outputPath] = compilation.assets[assetKey]
      }
    }

    compileCallback()
  })
})

module.exports = environment

I found this helpful - thanks!