Added $in and $notIn search operators (#98)

Resolves #97.

docs/v2/filtering.md

@@ -7,7 +7,8 @@ for controlled data retrieval.
 
 LDkit allows various search and filtering operations like `$equals`, `$not`,
 `$contains`, `$strStarts`, `$strEnds`, `$gt`, `$lt`, `$gte`, `$lte`, `$regex`,
-`$langMatches`, and `$filter`. Each is illustrated below with examples.
+`$langMatches`, `$in`, `$notIn`, and `$filter`. Each is illustrated below with
+examples.
 
 ### Simple example
 
@@ -70,6 +71,19 @@ await Persons.find({
 });
 ```
 
+### Array functions
+
+```typescript
+await Persons.find({
+  where: {
+    name: {
+      $in: ["Ada", "Alan"], // FILTER (?value IN ("Ada", "Alan"))
+      $notIn: ["Ada", "Alan"], // FILTER (?value NOT IN ("Ada", "Alan"))
+    },
+  },
+});
+```
+
 ### Custom filtering
 
 On top of the above, it is possible to specify a custom filter function using

library/lens/search_helper.ts

@@ -34,6 +34,7 @@ export class SearchHelper {
     this.processStringFunctions();
     this.processRegex();
     this.processLangMatches();
+    this.processArrayFunctions();
     this.processFilter();
   }
 
@@ -102,6 +103,25 @@ export class SearchHelper {
     );
   }
 
+  private processArrayFunctions() {
+    const map = {
+      $in: "IN",
+      $notIn: "NOT IN",
+    };
+
+    for (const [key, func] of Object.entries(map)) {
+      const value = this.searchSchema[key];
+      if (value === undefined) {
+        continue;
+      }
+
+      const values = (value as unknown[]).map((v) => $`${this.encode(v)}`);
+      this.addFilter(
+        $`${this.df.variable(this.varName)} ${func} (${values.join(", ")})`,
+      );
+    }
+  }
+
   private processFilter() {
     const value = this.searchSchema.$filter;
     if (value === undefined) {

library/schema/search.ts

@@ -12,6 +12,8 @@ export type SearchFilters<T> = T | {
   $lte?: T;
   $regex?: string;
   $langMatches?: string;
+  $in?: T[];
+  $notIn?: T[];
   $filter?: SparqlValue;
 };
 

tests/e2e/search.test.ts

@@ -217,3 +217,34 @@ Deno.test("E2E / Search / $filter", async () => {
   assertEquals(results.length, 1);
   assertEquals(results[0].name, "Quentin Tarantino");
 });
+
+Deno.test("E2E / Search / $in", async () => {
+  const { Directors } = init();
+
+  const results = await Directors.find({
+    where: {
+      name: {
+        $in: ["Quentin Tarantino", "Steven Spielberg"],
+      },
+    },
+  });
+
+  assertEquals(results.length, 2);
+  assertEquals(results[0].name, "Quentin Tarantino");
+  assertEquals(results[1].name, "Steven Spielberg");
+});
+
+Deno.test("E2E / Search / $notIn", async () => {
+  const { Directors } = init();
+
+  const results = await Directors.find({
+    where: {
+      name: {
+        $notIn: ["Quentin Tarantino", "Steven Spielberg"],
+      },
+    },
+  });
+
+  assertEquals(results.length, 1);
+  assertEquals(results[0].name, "Stanley Kubrick");
+});

tests/schema.test.ts

@@ -37,6 +37,8 @@ type PropertySearch<T> = T | {
   $lte?: T;
   $regex?: string;
   $langMatches?: string;
+  $in?: T[];
+  $notIn?: T[];
   $filter?: SparqlValue;
 };