feat(migrate) Allows for currentVersion to be async function

README.md

@@ -5,7 +5,7 @@ A database migration runner that
 - will run your migration functions
 - will find and run migrations based on your settings (defaults to latest version and a new database).
 - stops running migrations, when one fails
-- runs all remaining migrations, if `curVersion` is `null`.
+- runs all remaining migrations, if `currentVersion` is `null`.
 
 ## Usage
 
@@ -18,7 +18,7 @@ yarn add @klw/node-database-migration
 ```
 import { migrate } from "@klw/node-database-migration";
 
-const curVersion = null;
+const currentVersion = null;
 const migrations = {
  one: {
  version: "1",
@@ -37,7 +37,7 @@ const migrations = {
  },
 };
 
-const result = await migrate([migrations.one, migrations.two, migrations.three], curVersion);
+const result = await migrate([migrations.one, migrations.two, migrations.three], currentVersion);
 ```
 
 ### Your Migration Functions
@@ -56,11 +56,19 @@ You may add `options` to your migrations.
 
 ```
 const options = { targetVersion: "5" }
-const result = await migrate(migrations, curVersion, options);
+const result = await migrate(migrations, currentVersion, options);
 ```
 
 Currently only the `targetVersion` option is available. This will enable you to downgrade.
 
+You may pass an async function as `currentVersion`.
+
+```
+const result = await migrate(migrations, async () => Promise.resolve("X"));
+```
+
+This way you can avoid top level `await`, if needed.
+
 ## Return value
 
 The migration runner will stop running migrations, if one fails. In either case you will get a resolved `Promise`.

src/__tests__/index.test.ts

@@ -70,6 +70,20 @@ test("should run migrations UP, with current version supplied", async () => {
  expect(received).toEqual(expected);
 });
 
+test("should get version from async function", async () => {
+ const expected = {
+ success: true,
+ targetVersion: "3",
+ direction: "UP",
+ started: ["2", "3"],
+ fulfilled: ["2", "3"],
+ };
+ const received = await migrate([migrations.one.success, migrations.two.success, migrations.three.success], async () =>
+ Promise.resolve("1"),
+ );
+ expect(received).toEqual(expected);
+});
+
 test("should run migrations DOWN", async () => {
  const expected = {
  success: true,

src/index.ts

@@ -1,62 +1,4 @@
-import { runSequence } from "@klw/node-sequential-promises";
-import { Migration, MigrationOptions, MigrationResult, MigrationVersion } from "./types";
+import { migrate } from "./migrate";
+import { Migration, MigrationOptions, MigrationResult, MigrationVersion, MigrationError } from "./types";
 
-/**
- * Runs your database migrations up and down.
- *
- * @param migrations - Array of all Migrations. See docs/types for details.
- * @param currentVersion - The current version (or null) if the database is not set up yet.
- * @param options - Set the target version with {targetVersion: string}
- *
- * Will fallback to latest version, if target version is not specified.
- */
-export const migrate = async (
- migrations: Migration[],
- currentVersion: MigrationVersion | null,
- options?: MigrationOptions,
-): Promise<MigrationResult | undefined> => {
- const latestVersion = migrations[migrations.length - 1].version;
- const targetVersion = options?.targetVersion || "latest";
- const newVersion = targetVersion === "latest" ? latestVersion : targetVersion || latestVersion;
- const curVersionIndex = migrations.findIndex((x) => x.version === currentVersion);
- const newVersionIndex = migrations.findIndex((x) => x.version === newVersion);
-
- // Don't know what to do with not-matching version
- if (currentVersion && curVersionIndex === -1) {
- return Promise.reject(`No matching currentVersion (${currentVersion}) found.`);
- }
-
- // Define actual migrations to run
- const migrateUp = newVersionIndex >= curVersionIndex;
- const steps = migrateUp
- ? migrations.slice(curVersionIndex + 1, newVersionIndex + 1)
- : migrations.slice(newVersionIndex + 1, curVersionIndex + 1).reverse();
-
- // Target version number
- const returnTargetVersion = migrations[newVersionIndex].version;
-
- // No migrations to run
- if (steps.length === 0) {
- return Promise.resolve({
- success: true,
- started: [],
- fulfilled: [],
- direction: "UP",
- targetVersion: returnTargetVersion,
- });
- }
-
- // Actually run migrations
- const result = await runSequence(steps.map((step) => (migrateUp ? step.up : step.down)));
-
- const started = result.started.map((index) => steps[index].version);
- const fulfilled = result.fulfilled.map((index) => steps[index].version);
- return {
- targetVersion: returnTargetVersion,
- direction: migrateUp ? "UP" : "DOWN",
- success: result.success,
- started,
- fulfilled,
- errorMessage: result.error,
- };
-};
+export { migrate, Migration, MigrationOptions, MigrationResult, MigrationVersion, MigrationError };

src/migrate.ts

@@ -0,0 +1,63 @@
+import { runSequence } from "@klw/node-sequential-promises";
+import { Migration, MigrationOptions, MigrationResult, MigrationVersion } from "./types";
+
+/**
+ * Runs your database migrations up and down.
+ *
+ * @param migrations - Array of all Migrations. See docs/types for details.
+ * @param currentVersion - The current version (or null) if the database is not set up yet.
+ * @param options - Set the target version with {targetVersion: string}
+ *
+ * Will fallback to latest version, if target version is not specified.
+ */
+export const migrate = async (
+ migrations: Migration[],
+ currentVersion: MigrationVersion | null | (() => Promise<MigrationVersion | null>),
+ options?: MigrationOptions,
+): Promise<MigrationResult | undefined> => {
+ const curVersion = currentVersion instanceof Function ? await currentVersion() : currentVersion;
+ const latestVersion = migrations[migrations.length - 1].version;
+ const targetVersion = options?.targetVersion || "latest";
+ const newVersion = targetVersion === "latest" ? latestVersion : targetVersion || latestVersion;
+ const curVersionIndex = migrations.findIndex((x) => x.version === curVersion);
+ const newVersionIndex = migrations.findIndex((x) => x.version === newVersion);
+
+ // Don't know what to do with not-matching version
+ if (curVersion && curVersionIndex === -1) {
+ return Promise.reject(`No matching currentVersion (${curVersion}) found.`);
+ }
+
+ // Define actual migrations to run
+ const migrateUp = newVersionIndex >= curVersionIndex;
+ const steps = migrateUp
+ ? migrations.slice(curVersionIndex + 1, newVersionIndex + 1)
+ : migrations.slice(newVersionIndex + 1, curVersionIndex + 1).reverse();
+
+ // Target version number
+ const returnTargetVersion = migrations[newVersionIndex].version;
+
+ // No migrations to run
+ if (steps.length === 0) {
+ return Promise.resolve({
+ success: true,
+ started: [],
+ fulfilled: [],
+ direction: "UP",
+ targetVersion: returnTargetVersion,
+ });
+ }
+
+ // Actually run migrations
+ const result = await runSequence(steps.map((step) => (migrateUp ? step.up : step.down)));
+
+ const started = result.started.map((index) => steps[index].version);
+ const fulfilled = result.fulfilled.map((index) => steps[index].version);
+ return {
+ targetVersion: returnTargetVersion,
+ direction: migrateUp ? "UP" : "DOWN",
+ success: result.success,
+ started,
+ fulfilled,
+ errorMessage: result.error,
+ };
+};