refactor: simplify plugin interfaces by getting rid of the "type" property

This is to prepare for having packages that contains multiple different plugins in the same file.

.changeset/yellow-students-compare.md

@@ -0,0 +1,7 @@
+---
+'@emigrate/plugin-generate-js': minor
+'@emigrate/plugin-tools': minor
+'emigrate': minor
+---
+
+Simplify plugin interfaces by getting rid of the "type" string, in preparation for having packages that contains multiple different plugins

packages/emigrate/src/new-command.ts

@@ -62,7 +62,7 @@ export default async function newCommand({ directory, template, plugins, name, e
       throw new Error('No generator plugin found, please specify a generator plugin using the plugin option');
     }
 
-    const generated = await generatorPlugin.generate(name);
+    const generated = await generatorPlugin.generateMigration(name);
 
     filename = generated.filename;
     content = generated.content;

packages/plugin-generate-js/src/index.ts

@@ -1,6 +1,7 @@
-import { createGeneratorPlugin, getTimestampPrefix, sanitizeMigrationName } from '@emigrate/plugin-tools';
+import { getTimestampPrefix, sanitizeMigrationName } from '@emigrate/plugin-tools';
+import { type GenerateMigrationFunction } from '@emigrate/plugin-tools/types';
 
-export default createGeneratorPlugin(async (name) => {
+export const generateMigration: GenerateMigrationFunction = async (name) => {
   return {
     filename: `${getTimestampPrefix()}_${sanitizeMigrationName(name)}.js`,
     content: `// ${name}
@@ -9,4 +10,4 @@ export default async () => {
 };
 `,
   };
-});
+};

packages/plugin-tools/src/index.ts

@@ -1,30 +1,12 @@
 import process from 'node:process';
 import { type PluginFromType, type PluginType, type GeneratorPlugin, type StoragePlugin } from './types.js';
 
-export const createStoragePlugin = (initialize: StoragePlugin['initialize']): StoragePlugin => {
-  return {
-    type: 'storage',
-    initialize,
-  };
-};
-
-export const createGeneratorPlugin = (generate: GeneratorPlugin['generate']): GeneratorPlugin => {
-  return {
-    type: 'generator',
-    generate,
-  };
-};
-
 export const isGeneratorPlugin = (plugin: any): plugin is GeneratorPlugin => {
   if (!plugin || typeof plugin !== 'object') {
     return false;
   }
 
-  if (plugin.type === 'generator') {
-    return typeof plugin.generate === 'function';
-  }
-
-  return false;
+  return typeof plugin.generateMigration === 'function';
 };
 
 export const isStoragePlugin = (plugin: any): plugin is StoragePlugin => {
@@ -32,11 +14,7 @@ export const isStoragePlugin = (plugin: any): plugin is StoragePlugin => {
     return false;
   }
 
-  if (plugin.type === 'storage') {
-    return typeof plugin.initialize === 'function';
-  }
-
-  return false;
+  return typeof plugin.initializeStorage === 'function';
 };
 
 export const isPluginOfType = <T extends PluginType>(type: T, plugin: any): plugin is PluginFromType<T> => {

packages/plugin-tools/src/types.ts

@@ -57,10 +57,11 @@ export type Storage = {
 };
 
 export type StoragePlugin = {
-  type: 'storage';
-  initialize(): Promise<Storage>;
+  initializeStorage(): Promise<Storage>;
 };
 
+export type InitializeStorageFunction = StoragePlugin['initializeStorage'];
+
 export type MigrationFile = {
   /**
    * The complete filename of the migration file, including the extension.
@@ -75,18 +76,23 @@ export type MigrationFile = {
 };
 
 export type GeneratorPlugin = {
-  type: 'generator';
   /**
    * Used to generate a new migration file.
    *
    * @param name The name of the migration that should be generated (provided as arguments to the CLI)
    * @returns The generated migration file.
    */
-  generate(name: string): Promise<MigrationFile>;
+  generateMigration(name: string): Promise<MigrationFile>;
 };
 
+export type GenerateMigrationFunction = GeneratorPlugin['generateMigration'];
+
 export type Plugin = StoragePlugin | GeneratorPlugin;
 
-export type PluginType = Plugin['type'];
+export type PluginType = 'storage' | 'generator';
 
-export type PluginFromType<T extends PluginType> = Extract<Plugin, { type: T }>;
+export type PluginFromType<T extends PluginType> = T extends 'storage'
+  ? StoragePlugin
+  : T extends 'generator'
+  ? GeneratorPlugin
+  : never;