feat!: upgrade webpack to 5 and add TS support

Breaking flag is because it may have some differences in the way the library is exported -
`module.exports = ` vs `module.exports.default = `. That would depend on the Webpack config,
so it should continue working, but just to be safe.

jest.config.js

@@ -1,5 +1,37 @@
+const {createDefaultEsmPreset} = require('ts-jest');
+
+/** @type {import('ts-jest').JestConfigWithTsJest} */
 module.exports = {
+    moduleNameMapper: {
+        // Allows jest to find the asset files, otherwise it looks for them with the
+        // `?arrayBuffer` as part of the name and doesn't end up transforming them.
+        '^(.+)\\?arrayBuffer$': '$1'
+    },
+    moduleFileExtensions: ['ts', 'js'],
     transform: {
+        ...createDefaultEsmPreset({
+            tsconfig: 'tsconfig.test.json',
+
+            // The webpack 5 way to include web workers is to use
+            // `new Worker(new URL('./worker.js', import.meta.url));`.
+            // See https://webpack.js.org/guides/web-workers/
+            // However, the `import.meta.url` is ESM-only and Jest's support for ESM is
+            // still experimental. So, we need to mock it instead (or use experimental
+            // jest & node features).
+            //
+            // Also see https://www.npmjs.com/package/ts-jest-mock-import-meta
+            diagnostics: {
+                ignoreCodes: [1343]
+            },
+            astTransformers: {
+                before: [
+                    {
+                        path: 'ts-jest-mock-import-meta',
+                        options: {metaObjectReplacement: {url: 'https://example.com'}}
+                    }
+                ]
+            }
+        }).transform,
         '\\.(png|svg|wav)$': '<rootDir>/test/transformers/arraybuffer-loader.js'
     }
 };