feat(core): Create a dsl for writing db agnostic migrations (#6853)

packages/cli/src/databases/dsl/Indices.ts

@@ -0,0 +1,45 @@
+import { QueryRunner, TableIndex } from 'typeorm';
+import LazyPromise from 'p-lazy';
+
+abstract class IndexOperation extends LazyPromise<void> {
+	abstract execute(queryRunner: QueryRunner): Promise<void>;
+
+	constructor(
+		protected name: string,
+		protected tableName: string,
+		protected prefix: string,
+		queryRunner: QueryRunner,
+	) {
+		super((resolve) => {
+			void this.execute(queryRunner).then(resolve);
+		});
+	}
+}
+
+export class CreateIndex extends IndexOperation {
+	constructor(
+		name: string,
+		tableName: string,
+		protected columnNames: string[],
+		protected isUnique: boolean,
+		prefix: string,
+		queryRunner: QueryRunner,
+	) {
+		super(name, tableName, prefix, queryRunner);
+	}
+
+	async execute(queryRunner: QueryRunner) {
+		const { tableName, name, columnNames, prefix, isUnique } = this;
+		return queryRunner.createIndex(
+			`${prefix}${tableName}`,
+			new TableIndex({ name: `IDX_${prefix}${name}`, columnNames, isUnique }),
+		);
+	}
+}
+
+export class DropIndex extends IndexOperation {
+	async execute(queryRunner: QueryRunner) {
+		const { tableName, name, prefix } = this;
+		return queryRunner.dropIndex(`${prefix}${tableName}`, `IDX_${prefix}${name}`);
+	}
+}