feat: add ability to clone models (use same model under different nam…

…e in a repository)

src/__tests__/clone.test.ts

@@ -0,0 +1,89 @@
+import * as semanticLayer from "../index.js";
+
+import { assert, describe, it } from "vitest";
+
+const userModel = semanticLayer
+  .model()
+  .withName("user")
+  .fromTable("User")
+  .withDimension("user_id", {
+    type: "number",
+    primaryKey: true,
+    sql: ({ model, sql }) => sql`${model.column("UserId")}`,
+  })
+  .withDimension("first_name", {
+    type: "string",
+    sql: ({ model }) => model.column("FirstName"),
+  })
+  .withDimension("last_name", {
+    type: "string",
+    sql: ({ model }) => model.column("LastName"),
+  })
+  .withMetric("count", {
+    type: "string",
+    sql: ({ model, sql }) => sql`COUNT(DISTINCT ${model.column("UserId")})`,
+  });
+
+const customerModel = userModel.clone("customer");
+const employeeModel = userModel.clone("employee");
+
+const invoiceModel = semanticLayer
+  .model()
+  .withName("invoice")
+  .fromTable("Invoice")
+  .withDimension("invoice_id", {
+    type: "number",
+    primaryKey: true,
+    sql: ({ model }) => model.column("InvoiceId"),
+  })
+  .withDimension("customer_id", {
+    type: "number",
+    sql: ({ model }) => model.column("CustomerId"),
+  })
+  .withDimension("employee_id", {
+    type: "number",
+    sql: ({ model }) => model.column("EmployeeId"),
+  });
+
+const repository = semanticLayer
+  .repository()
+  .withModel(customerModel)
+  .withModel(employeeModel)
+  .withModel(invoiceModel)
+  .joinOneToMany(
+    "customer",
+    "invoice",
+    ({ sql, models }) =>
+      sql`${models.customer.dimension("user_id")} = ${models.invoice.dimension(
+        "customer_id",
+      )}`,
+  )
+  .joinOneToMany(
+    "employee",
+    "invoice",
+    ({ sql, models }) =>
+      sql`${models.employee.dimension("user_id")} = ${models.invoice.dimension(
+        "employee_id",
+      )}`,
+  );
+
+const queryBuilder = repository.build("postgresql");
+
+describe("clone", async () => {
+  it("can clone a model", async () => {
+    const query = queryBuilder.buildQuery({
+      members: [
+        "customer.user_id",
+        "customer.count",
+        "employee.user_id",
+        "employee.count",
+        "invoice.invoice_id",
+      ],
+    });
+
+    assert.equal(
+      query.sql,
+      'select "q0"."customer___user_id" as "customer___user_id", "q0"."employee___user_id" as "employee___user_id", "q0"."invoice___invoice_id" as "invoice___invoice_id", "q0"."customer___count" as "customer___count", "q1"."employee___count" as "employee___count" from (select "customer_query"."customer___user_id" as "customer___user_id", "customer_query"."employee___user_id" as "employee___user_id", "customer_query"."invoice___invoice_id" as "invoice___invoice_id", COUNT(DISTINCT count___metric_ref_0) as "customer___count" from (select distinct "User"."UserId" AS "count___metric_ref_0", "User"."UserId" as "customer___user_id", "Invoice"."InvoiceId" as "invoice___invoice_id", "User"."UserId" as "employee___user_id" from "User" left join "Invoice" on "User"."UserId" = "Invoice"."CustomerId" right join "User" on "User"."UserId" = "Invoice"."EmployeeId") as "customer_query" group by "customer_query"."customer___user_id", "customer_query"."employee___user_id", "customer_query"."invoice___invoice_id") as "q0" inner join (select "employee_query"."customer___user_id" as "customer___user_id", "employee_query"."employee___user_id" as "employee___user_id", "employee_query"."invoice___invoice_id" as "invoice___invoice_id", COUNT(DISTINCT count___metric_ref_0) as "employee___count" from (select distinct "User"."UserId" AS "count___metric_ref_0", "User"."UserId" as "employee___user_id", "Invoice"."InvoiceId" as "invoice___invoice_id", "User"."UserId" as "customer___user_id" from "User" left join "Invoice" on "User"."UserId" = "Invoice"."EmployeeId" right join "User" on "User"."UserId" = "Invoice"."CustomerId") as "employee_query" group by "employee_query"."customer___user_id", "employee_query"."employee___user_id", "employee_query"."invoice___invoice_id") as "q1" on "q0"."customer___user_id" = "q1"."customer___user_id" and "q0"."employee___user_id" = "q1"."employee___user_id" and "q0"."invoice___invoice_id" = "q1"."invoice___invoice_id" order by "customer___count" desc limit $1 offset $2',
+    );
+  });
+});

src/lib/model.ts

@@ -258,6 +258,7 @@ export abstract class Member {
   getFormat() {
     return this.props.format;
   }
+  abstract clone(model: AnyModel): Member;
 }
 
 export class Dimension extends Member {
@@ -269,6 +270,9 @@ export class Dimension extends Member {
   ) {
     super();
   }
+  clone(model: AnyModel) {
+    return new Dimension(model, this.name, { ...this.props }, this.granularity);
+  }
   getSql(dialect: AnyBaseDialect, context: unknown) {
     const result = this.getSqlWithoutGranularity(dialect, context);
 
@@ -319,6 +323,9 @@ export class Metric extends Member {
   ) {
     super();
   }
+  clone(model: AnyModel) {
+    return new Metric(model, this.name, { ...this.props });
+  }
   getNextColumnRefOrDimensionRefAlias() {
     let columnRefOrDimensionRefAliasCounter = 0;
     return () =>
@@ -493,6 +500,16 @@ export class Model<
     });
     return result.render(dialect, context);
   }
+  clone<N extends string>(name: N) {
+    const newModel = new Model<C, N, D, M>(name, this.config);
+    for (const [key, value] of Object.entries(this.dimensions)) {
+      newModel.dimensions[key] = value.clone(newModel);
+    }
+    for (const [key, value] of Object.entries(this.metrics)) {
+      newModel.metrics[key] = value.clone(newModel);
+    }
+    return newModel;
+  }
 }
 
 const VALID_NAME_RE = /^[a-zA-Z_][a-zA-Z0-9_]*$/;