feat: support static placeholders with sql template

src/database.ts

@@ -1,4 +1,5 @@
-import type { Connector, Database, Primitive } from "./types";
+import { sqlTemplate } from "./template";
+import type { Connector, Database } from "./types";
 
 const SQL_WITH_RES_RE = /^select/i;
 
@@ -26,28 +27,3 @@ export function createDatabase(connector: Connector): Database {
     },
   };
 }
-
-export function sqlTemplate(
-  strings: TemplateStringsArray,
-  ...values: Primitive[]
-): [string, Primitive[]] {
-  if (!isTemplateStringsArray(strings) || !Array.isArray(values)) {
-    throw new Error("[db0] invalid template invokation");
-  }
-
-  let result = strings[0] || "";
-
-  for (let i = 1; i < strings.length; i++) {
-    result += `?${strings[i] ?? ""}`;
-  }
-
-  return [result, values];
-}
-
-function isTemplateStringsArray(
-  strings: unknown,
-): strings is TemplateStringsArray {
-  return (
-    Array.isArray(strings) && "raw" in strings && Array.isArray(strings.raw)
-  );
-}

src/template.ts

@@ -0,0 +1,34 @@
+import type { Primitive } from "./types";
+
+export function sqlTemplate(
+  strings: TemplateStringsArray,
+  ...values: Primitive[]
+): [string, Primitive[]] {
+  if (!isTemplateStringsArray(strings) || !Array.isArray(values)) {
+    throw new Error("[db0] invalid template invokation");
+  }
+
+  const staticIndexes: number[] = [];
+
+  let result = strings[0] || "";
+  for (let i = 1; i < strings.length; i++) {
+    if (result.endsWith("{") && strings[i].startsWith("}")) {
+      result = result.slice(0, -1) + values[i - 1] + strings[i].slice(1);
+      staticIndexes.push(i - 1);
+      continue;
+    }
+    result += `?${strings[i] ?? ""}`;
+  }
+
+  const dynamicValues = values.filter((_, i) => !staticIndexes.includes(i));
+
+  return [result.trim(), dynamicValues];
+}
+
+function isTemplateStringsArray(
+  strings: unknown,
+): strings is TemplateStringsArray {
+  return (
+    Array.isArray(strings) && "raw" in strings && Array.isArray(strings.raw)
+  );
+}

src/types.ts

@@ -15,13 +15,18 @@ export type Connector = {
   prepare: (sql: string) => Statement;
 };
 
-type SqlTemplate<T> = (
-  strings: TemplateStringsArray,
-  ...values: Primitive[]
-) => T;
+type DefaultSQLResult = {
+  lastInsertRowid?: number;
+  changes?: number;
+  error?: string;
+  rows?: { id?: string | number; [key: string]: unknown }[];
+};
 
-export type Database = {
+export interface Database {
   exec: (sql: string) => Promise<ExecResult>;
   prepare: (sql: string) => Statement;
-  sql: SqlTemplate<Promise<{ rows?: unknown[]; [key: string]: unknown }>>;
-};
+  sql: <T = DefaultSQLResult>(
+    strings: TemplateStringsArray,
+    ...values: Primitive[]
+  ) => Promise<T>;
+}

test/template.test.ts

@@ -0,0 +1,24 @@
+import { describe, it, expect } from "vitest";
+import { sqlTemplate } from "../src/template";
+
+describe("SQL Template", () => {
+  const tests = [
+    {
+      sql: sqlTemplate`SELECT * FROM {${"users"}} WHERE age > ${25} AND type = ${"test"}`,
+      query: "SELECT * FROM users WHERE age > ? AND type = ?",
+      values: [25, "test"],
+    },
+    {
+      sql: sqlTemplate`INSERT INTO {${"users"}} ({${"name"}}, {${"age"}}) VALUES (${25}, ${"test"})`,
+      query: "INSERT INTO users (name, age) VALUES (?, ?)",
+      values: [25, "test"],
+    },
+  ];
+
+  for (const test of tests) {
+    const testName = `${test.query} (${test.values.join(", ")}))`;
+    it(testName, () => {
+      expect(test.sql).toEqual([test.query, test.values]);
+    });
+  }
+});