From cb113dd2a65d9a650c25fb6cb56e371dd07b2ae5 Mon Sep 17 00:00:00 2001
From: Mark Stacey <markjstacey@gmail.com>
Date: Mon, 27 Feb 2023 15:16:22 -0330
Subject: [PATCH] Convert the migration template to TypeScript (#17836)

The migration template has been converted to TypeScript. We can start
writing migrations in TypeScript today; they have no dependencies on
JavaScript modules.
---
 app/scripts/migrations/template.js      | 29 -------------------------
 app/scripts/migrations/template.test.js |  8 +++----
 app/scripts/migrations/template.ts      | 28 ++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 33 deletions(-)
 delete mode 100644 app/scripts/migrations/template.js
 create mode 100644 app/scripts/migrations/template.ts

diff --git a/app/scripts/migrations/template.js b/app/scripts/migrations/template.js
deleted file mode 100644
index b3f050dfc..000000000
--- a/app/scripts/migrations/template.js
+++ /dev/null
@@ -1,29 +0,0 @@
-// next version number
-/*
-
-description of migration and what it does
-
-*/
-
-import { cloneDeep } from 'lodash';
-
-const version = 0;
-
-export default {
-  version,
-
-  async migrate(originalVersionedData) {
-    const versionedData = cloneDeep(originalVersionedData);
-    versionedData.meta.version = version;
-    const state = versionedData.data;
-    const newState = transformState(state);
-    versionedData.data = newState;
-    return versionedData;
-  },
-};
-
-function transformState(state) {
-  const newState = state;
-  // transform state here
-  return newState;
-}
diff --git a/app/scripts/migrations/template.test.js b/app/scripts/migrations/template.test.js
index f24dc1bca..2c0e0bcc9 100644
--- a/app/scripts/migrations/template.test.js
+++ b/app/scripts/migrations/template.test.js
@@ -1,13 +1,13 @@
-import migrationTemplate from './template';
+import { migrate, version } from './template';
 
 const storage = {
-  meta: {},
+  meta: { version: -1 },
   data: {},
 };
 
 describe('storage is migrated successfully', () => {
   it('should work', async () => {
-    const migratedData = await migrationTemplate.migrate(storage);
-    expect(migratedData.meta.version).toStrictEqual(0);
+    const migratedData = await migrate(storage);
+    expect(migratedData.meta.version).toStrictEqual(version);
   });
 });
diff --git a/app/scripts/migrations/template.ts b/app/scripts/migrations/template.ts
new file mode 100644
index 000000000..e9c70cd47
--- /dev/null
+++ b/app/scripts/migrations/template.ts
@@ -0,0 +1,28 @@
+import { cloneDeep } from 'lodash';
+
+export const version = 0;
+
+/**
+ * Explain the purpose of the migration here.
+ *
+ * @param originalVersionedData - Versioned MetaMask extension state, exactly what we persist to dist.
+ * @param originalVersionedData.meta - State metadata.
+ * @param originalVersionedData.meta.version - The current state version.
+ * @param originalVersionedData.data - The persisted MetaMask state, keyed by controller.
+ * @returns Updated versioned MetaMask extension state.
+ */
+export async function migrate(originalVersionedData: {
+  meta: { version: number };
+  data: Record<string, unknown>;
+}) {
+  const versionedData = cloneDeep(originalVersionedData);
+  versionedData.meta.version = version;
+  versionedData.data = transformState(versionedData.data);
+  return versionedData;
+}
+
+function transformState(state: Record<string, unknown>) {
+  const newState = state;
+  // transform state here
+  return newState;
+}