Add join nested (#31)

Signed-off-by: Tobias Gurtzick <[email protected]>

src/index.spec.ts

@@ -1,6 +1,6 @@
 import { inspect } from "util";
 import { describe, it, expect } from "@jest/globals";
-import sql, { empty, join, raw, Sql } from "./index.js";
+import sql, { empty, join, joinNested, raw, Sql } from "./index.js";
 
 describe("sql template tag", () => {
   it("should generate sql", () => {
@@ -149,4 +149,27 @@ describe("sql template tag", () => {
       expect(query.values).toEqual([value]);
     });
   });
+
+  describe("joinNested", () => {
+    it("should join nested list", () => {
+      const query = joinNested([
+        [1, 2, 3],
+        [5, 2, 3],
+      ]);
+
+      expect(query.text).toEqual("($1,$2,$3),($4,$5,$6)");
+      expect(query.values).toEqual([1, 2, 3, 5, 2, 3]);
+    });
+
+    it("should error joining an empty list", () => {
+      expect(() => joinNested([])).toThrowError(TypeError);
+    });
+
+    it("should error joining an nested empty list", () => {
+      expect(() => joinNested([[]])).toThrowError(TypeError);
+    });
+    it("should error joining an nested non uniform list", () => {
+      expect(() => joinNested([[1, 2], [1, 3], [1]])).toThrowError(TypeError);
+    });
+  });
 });

src/index.ts

@@ -110,6 +110,38 @@ export function join(
   );
 }
 
+/**
+ * Create a SQL query for a list of structred values. Very useful for bulk
+ * inserts.
+ */
+export function joinNested(values: Array<RawValue[]>, separator = ",") {
+  if (values.length === 0) {
+    throw new TypeError(
+      "Expected `joinNested([][])` to be called with an array of multiple elements, but got an empty array"
+    );
+  }
+
+  const len = values[0].length;
+
+  if (len === 0) {
+    throw new TypeError(
+      "Expected `joinNested([][])` to be called with an nested array of multiple elements, but got an empty array"
+    );
+  }
+
+  const v = values.map((x, index) => {
+    if (x.length !== len) {
+      throw new TypeError(
+        `Expected joinNested([][${len}]) instead param at index ${index} had a length of ${x.length}`
+      );
+    }
+
+    return new Sql(["(", ...Array(x.length - 1).fill(separator), ")"], x);
+  });
+
+  return new Sql(["", ...Array(v.length - 1).fill(separator), ""], v);
+}
+
 /**
  * Create raw SQL statement.
  */