diff --git a/scripts/build/cache.js b/scripts/build/cache.js
index 1bcb061a9..ae599f0a1 100644
--- a/scripts/build/cache.js
+++ b/scripts/build/cache.js
@@ -1,7 +1,7 @@
 "use strict";
 
 const util = require("util");
-const assert = require("assert");
+const assert = require("assert").strict;
 const crypto = require("crypto");
 const fs = require("fs");
 const path = require("path");
@@ -12,97 +12,99 @@ const writeFile = util.promisify(fs.writeFile);
 
 const ROOT = path.join(__dirname, "..", "..");
 
-function Cache(cacheDir, version) {
-  this.cacheDir = path.resolve(cacheDir || required("cacheDir"));
-  this.manifest = path.join(this.cacheDir, "manifest.json");
-  this.version = version || required("version");
-  this.checksums = {};
-  this.files = {};
-  this.updated = {
-    version: this.version,
-    checksums: {},
-    files: {},
-  };
-}
-
-// Loads the manifest.json file with the information from the last build
-Cache.prototype.load = async function () {
-  // This should never throw, if it does, let it fail the build
-  const lockfile = await readFile("yarn.lock", "utf-8");
-  const lockfileHash = hashString(lockfile);
-  this.updated.checksums["yarn.lock"] = lockfileHash;
-
-  try {
-    const manifest = await readFile(this.manifest, "utf-8");
-    const { version, checksums, files } = JSON.parse(manifest);
-
-    // Ignore the cache if the version changed
-    assert.equal(this.version, version);
-
-    assert.ok(typeof checksums === "object");
-    // If yarn.lock changed, rebuild everything
-    assert.equal(lockfileHash, checksums["yarn.lock"]);
-    this.checksums = checksums;
-
-    assert.ok(typeof files === "object");
-    this.files = files;
-
-    for (const files of Object.values(this.files)) {
-      assert.ok(Array.isArray(files));
-    }
-  } catch (err) {
+class Cache {
+  constructor(cacheDir, version) {
+    this.cacheDir = path.resolve(cacheDir || required("cacheDir"));
+    this.manifest = path.join(this.cacheDir, "manifest.json");
+    this.version = version || required("version");
     this.checksums = {};
     this.files = {};
+    this.updated = {
+      version: this.version,
+      checksums: {},
+      files: {},
+    };
   }
-};
 
-// Run rollup to get the list of files included in the bundle and check if
-// any (or the list itself) have changed.
-// This takes the same rollup config used for bundling to include files that are
-// resolved by specific plugins.
-Cache.prototype.checkBundle = async function (id, inputOptions, outputOptions) {
-  const files = new Set(this.files[id]);
-  const newFiles = (this.updated.files[id] = []);
+  // Loads the manifest.json file with the information from the last build
+  async load() {
+    // This should never throw, if it does, let it fail the build
+    const lockfile = await readFile("yarn.lock", "utf-8");
+    const lockfileHash = hashString(lockfile);
+    this.updated.checksums["yarn.lock"] = lockfileHash;
 
-  let dirty = false;
+    try {
+      const manifest = await readFile(this.manifest, "utf-8");
+      const { version, checksums, files } = JSON.parse(manifest);
 
-  const bundle = await rollup(getRollupConfig(inputOptions));
-  const { output } = await bundle.generate(outputOptions);
+      // Ignore the cache if the version changed
+      assert.strictEqual(this.version, version);
 
-  const modules = output
-    .filter((mod) => !/\0/.test(mod.facadeModuleId))
-    .map((mod) => [path.relative(ROOT, mod.facadeModuleId), mod.code]);
+      assert.ok(typeof checksums === "object");
+      // If yarn.lock changed, rebuild everything
+      assert.strictEqual(lockfileHash, checksums["yarn.lock"]);
+      this.checksums = checksums;
 
-  for (const [id, code] of modules) {
-    newFiles.push(id);
-    // If we already checked this file for another bundle, reuse the hash
-    if (!this.updated.checksums[id]) {
-      this.updated.checksums[id] = hashString(code);
-    }
-    const hash = this.updated.checksums[id];
+      assert.ok(typeof files === "object");
+      this.files = files;
 
-    // Check if this file changed
-    if (!this.checksums[id] || this.checksums[id] !== hash) {
-      dirty = true;
-    }
-
-    // Check if this file is new
-    if (!files.delete(id)) {
-      dirty = true;
+      for (const files of Object.values(this.files)) {
+        assert.ok(Array.isArray(files));
+      }
+    } catch (err) {
+      this.checksums = {};
+      this.files = {};
     }
   }
 
-  // Final check: if any file was removed, `files` is not empty
-  return !dirty && files.size === 0;
-};
+  // Run rollup to get the list of files included in the bundle and check if
+  // any (or the list itself) have changed.
+  // This takes the same rollup config used for bundling to include files that are
+  // resolved by specific plugins.
+  async checkBundle(id, inputOptions, outputOptions) {
+    const files = new Set(this.files[id]);
+    const newFiles = (this.updated.files[id] = []);
 
-Cache.prototype.save = async function () {
-  try {
-    await writeFile(this.manifest, JSON.stringify(this.updated, null, 2));
-  } catch (err) {
-    // Don't fail the build
+    let dirty = false;
+
+    const bundle = await rollup(getRollupConfig(inputOptions));
+    const { output } = await bundle.generate(outputOptions);
+
+    const modules = output
+      .filter((mod) => !/\0/.test(mod.facadeModuleId))
+      .map((mod) => [path.relative(ROOT, mod.facadeModuleId), mod.code]);
+
+    for (const [id, code] of modules) {
+      newFiles.push(id);
+      // If we already checked this file for another bundle, reuse the hash
+      if (!this.updated.checksums[id]) {
+        this.updated.checksums[id] = hashString(code);
+      }
+      const hash = this.updated.checksums[id];
+
+      // Check if this file changed
+      if (!this.checksums[id] || this.checksums[id] !== hash) {
+        dirty = true;
+      }
+
+      // Check if this file is new
+      if (!files.delete(id)) {
+        dirty = true;
+      }
+    }
+
+    // Final check: if any file was removed, `files` is not empty
+    return !dirty && files.size === 0;
   }
-};
+
+  async save() {
+    try {
+      await writeFile(this.manifest, JSON.stringify(this.updated, null, 2));
+    } catch (err) {
+      // Don't fail the build
+    }
+  }
+}
 
 function required(name) {
   throw new Error(name + " is required");