A simple snowpack plugin for generating a .d.ts file for paths inside an asset folder

snowpack-plugin-assets.js

// @ts-check

const fs = require("fs")
const { join, basename } = require("path")
const { format } = require("prettier")

let log = undefined

/** @type {import("snowpack").SnowpackPluginFactory} */
function plugin(_snowpackConfig, _pluginOptions) {
  return {
    name: "snowpack-plugin-phaser-assets",
    async run(opts) {
      const backupLog = (_, opts) => opts.msg && console.log(opts.msg)
      // @ts-ignore - This logging API is private, so it will change in the future
      log = opts.log || backupLog
      createTypedefs()
    },
    async onChange(opts) {
      if (opts.filePath.includes("assets")) createTypedefs()
    },
  }
}

const createTypedefs = () => {
  const publicRoot = join(__dirname, "..", "..", "public")
  const sourceFile = join(__dirname, "..", "..", "src", "game")

  const allFiles = getFilePaths(publicRoot)
  const files = allFiles.map(f => f.replace(publicRoot + "/", ""))

  const toID = str => {
    if (!str.includes("/")) return false
    return str.toLowerCase().replace(/\s/g, "-").split(".")[0].split("/").pop()
  }

  const code = `
/** All asset files */
export type Files = "${files.join('" | "')}"

/** IDs for any non-root file */
export type IDs = "${files.map(toID).filter(Boolean).join('" | "')}"
`

  const typePath = join(sourceFile, "paths.d.ts")
  fs.writeFileSync(typePath, format(code, { filepath: typePath }))

  log("WORKER_RESET", {})
  const date = new Intl.DateTimeFormat("en-US", { minute: "numeric", hour: "numeric", second: "numeric" }).format(new Date())
  log("WORKER_MSG", { level: "log", msg: `${date} - Updated asset type definitions.` })
}

// prettier-ignore
const getFilePaths = folderPath => {
  const entryPaths = fs.readdirSync(folderPath).map(entry => join(folderPath, entry));
  const filePaths = entryPaths.filter(entryPath => fs.statSync(entryPath).isFile());
  const dirPaths = entryPaths.filter(entryPath => !filePaths.includes(entryPath));
  const dirFiles = dirPaths.reduce((prev, curr) => prev.concat(getFilePaths(curr)), []);
  return [...filePaths, ...dirFiles].filter((f) => !basename(f).startsWith("."));
};

module.exports = plugin