feat: migrations can be provided as a map of loaded modules closes #203

Readme.md

@@ -230,6 +230,7 @@ Calls the callback with a `Set` based on the options passed.  Options:
 
 - `set`: A set instance if you created your own
 - `stateStore`: A store instance to load and store migration state, or a string which is a path to the migration state file
+- `migrations`: An object where keys are migration names and values are migration objects
 - `migrationsDirectory`: The path to the migrations directory
 - `filterFunction`: A filter function which will be called for each file found in the migrations directory
 - `sortFunction`: A sort function to ensure migration order

index.d.ts

@@ -3,6 +3,7 @@ import type { EventEmitter } from "events";
 type MigrationOptions = {
   set?: MigrationSet;
   stateStore?: string | FileStore;
+  migrations?: { [key: string]: { up: Function, down: Function } };
   migrationsDirectory?: string;
   ignoreMissing?: boolean;
   filterFunction?: (migration: string) => boolean;

index.js

@@ -53,6 +53,7 @@ exports.load = function (options, fn) {
   loadMigrationsIntoSet({
     set,
     store,
+    migrations: opts.migrations,
     migrationsDirectory: opts.migrationsDirectory,
     filterFunction: opts.filterFunction,
     sortFunction: opts.sortFunction,

lib/load-migrations.js

@@ -7,6 +7,47 @@ const Migration = require('./migration')
 
 module.exports = loadMigrationsIntoSet
 
+async function loadFromMigrationsDirectory (migrationsDirectory, filterFn) {
+  // Read migrations directory
+  let files = await fs.readdir(migrationsDirectory)
+
+  // Filter out non-matching files
+  files = files.filter(filterFn)
+
+  const migMap = {}
+  const promises = files.map(async function (file) {
+    // Try to load the migrations file
+    const filepath = path.join(migrationsDirectory, file)
+    let mod
+    try {
+      mod = require(filepath)
+    } catch (e) {
+      if (e.code === 'ERR_REQUIRE_ESM') {
+        mod = await import(url.pathToFileURL(filepath))
+      } else {
+        throw e
+      }
+    }
+
+    const migration = new Migration(file, mod.up, mod.down, mod.description)
+    migMap[file] = migration
+    return migration
+  })
+  await Promise.all(promises)
+  return migMap
+}
+
+function loadFromMigrations (migrations, filterFn) {
+  return Object
+    .keys(migrations)
+    .filter(filterFn)
+    .reduce((migMap, migrationName) => {
+      const mod = migrations[migrationName]
+      migMap[migrationName] = new Migration(migrationName, mod.up, mod.down, mod.description)
+      return migMap
+    }, {})
+}
+
 function loadMigrationsIntoSet (options, fn) {
   // Process options, set and store are required, rest optional
   const opts = options || {}
@@ -16,6 +57,7 @@ function loadMigrationsIntoSet (options, fn) {
   const set = opts.set
   const store = opts.store
   const ignoreMissing = !!opts.ignoreMissing
+  const migrations = opts.migrations
   const migrationsDirectory = path.resolve(opts.migrationsDirectory || 'migrations')
   const filterFn = opts.filterFunction || (() => true)
   const sortFn = opts.sortFunction || function (m1, m2) {
@@ -30,33 +72,10 @@ function loadMigrationsIntoSet (options, fn) {
       // Set last run date on the set
       set.lastRun = state.lastRun || null
 
-      // Read migrations directory
-      let files = await fs.readdir(migrationsDirectory)
-
-      // Filter out non-matching files
-      files = files.filter(filterFn)
-
       // Create migrations, keep a lookup map for the next step
-      const migMap = {}
-      const promises = files.map(async function (file) {
-        // Try to load the migrations file
-        const filepath = path.join(migrationsDirectory, file)
-        let mod
-        try {
-          mod = require(filepath)
-        } catch (e) {
-          if (e.code === 'ERR_REQUIRE_ESM') {
-            mod = await import(url.pathToFileURL(filepath))
-          } else {
-            return fn(e)
-          }
-        }
-
-        const migration = new Migration(file, mod.up, mod.down, mod.description)
-        migMap[file] = migration
-        return migration
-      })
-      let migrations = await Promise.all(promises)
+      const migMap = (migrations)
+        ? loadFromMigrations(migrations, filterFn)
+        : await loadFromMigrationsDirectory(migrationsDirectory, filterFn)
 
       // Fill in timestamp from state, or error if missing
       state.migrations && state.migrations.forEach(function (m) {
@@ -69,11 +88,10 @@ function loadMigrationsIntoSet (options, fn) {
         migMap[m.title].timestamp = m.timestamp
       })
 
-      // Sort the migrations by their title
-      migrations = migrations.sort(sortFn)
-
-      // Add the migrations to the set
-      migrations.forEach(set.addMigration.bind(set))
+      Object
+        .values(migMap)
+        .sort(sortFn)
+        .forEach(set.addMigration.bind(set))
 
       // Successfully loaded
       fn()