feat(core): improve support for ts-node

Previously one could setup ORM either for vanilla node, or for ts-node.
Now it will automatically check whether you used node or ts-node and
choose correct entities directory.

When running via ts-node, entitiesDirs option will be ignored, and
entitiesDirsTs will be used instead.

lib/metadata/MetadataDiscovery.ts

@@ -28,6 +28,8 @@ export class MetadataDiscovery {
 
     if (this.config.get('entities').length > 0) {
       await Promise.all(this.config.get('entities').map(entity => this.discoverEntity(entity)));
+    } else if (process.argv[0].endsWith('ts-node')) {
+      await Promise.all(this.config.get('entitiesDirsTs').map(dir => this.discoverDirectory(dir)));
     } else {
       await Promise.all(this.config.get('entitiesDirs').map(dir => this.discoverDirectory(dir)));
     }

tests/bootstrap.ts

@@ -23,8 +23,12 @@ export async function initORM() {
     hash = '-' + Math.random().toString(36).substring(6);
   }
 
+  // simulate ts-node to raise coverage
+  process.argv[0] = process.argv[0].replace(/node$/, 'ts-node');
+
   return MikroORM.init({
-    entitiesDirs: ['entities'],
+    entitiesDirs: ['dist/entities'], // will be ignored as we simulate ts-node
+    entitiesDirsTs: ['entities'],
     dbName: `mikro-orm-test${hash}`,
     baseDir: BASE_DIR,
     debug: true,