add: include and exclude filters for pagination

src/Plugins/Pagination.js

@@ -98,17 +98,39 @@ class Pagination {
 		return false;
 	}
 
-	isFiltered(value) {
+	isIncluded(value) {
+		const hasInclude = "include" in this.data.pagination;
+		const hasExclude = "exclude" in this.data.pagination;
+		if (hasInclude && hasExclude) {
+			throw new Error("Pagination cannot have both `include` and `exclude` properties.");
+		}
+		if (hasInclude) {
+			let included = this.data.pagination.include;
+			if (Array.isArray(included)) {
+				return included.includes(value);
+			}
+			return included === value;
+		}
+		if (hasExclude) {
+			let excluded = this.data.pagination.exclude;
+			if (Array.isArray(excluded)) {
+				return !excluded.includes(value);
+			}
+			return excluded !== value;
+		}
+
+		// Let's keep this code for backwards compatibility to V2.
+		// TODO remove in 3.0
 		if ("filter" in this.data.pagination) {
 			let filtered = this.data.pagination.filter;
 			if (Array.isArray(filtered)) {
-				return filtered.indexOf(value) > -1;
+				return filtered.indexOf(value) === -1;
 			}
 
-			return filtered === value;
+			return filtered !== value;
 		}
 
-		return false;
+		return true;
 	}
 
 	_has(target, key) {
@@ -162,8 +184,12 @@ class Pagination {
 			result = result.reverse();
 		}
 
-		if (this.data.pagination.filter) {
-			result = result.filter((value) => !this.isFiltered(value));
+		if (
+			this.data.pagination.filter ||
+			this.data.pagination.include ||
+			this.data.pagination.exclude
+		) {
+			result = result.filter((value) => this.isIncluded(value));
 		}
 
 		return result;

test/PaginationTest.js

@@ -498,6 +498,49 @@ test("Page over an object (use values)", async (t) => {
   );
 });
 
+test("Page over an object (excluded, array)", async (t) => {
+  let tmpl = await getNewTemplate(
+    "./test/stubs/paged/pagedobjectexcludearray.njk",
+    "./test/stubs/",
+    "./dist"
+  );
+
+  let data = await tmpl.getData();
+  let pages = await tmpl.getTemplates(data);
+
+  t.is(
+    (await pages[0].template.render(pages[0].data)).trim(),
+    "<ol><li>item1</li><li>item2</li><li>item3</li><li>item5</li></ol>"
+  );
+
+  t.is(
+    (await pages[1].template.render(pages[1].data)).trim(),
+    "<ol><li>item6</li><li>item7</li><li>item8</li><li>item9</li></ol>"
+  );
+});
+
+test("Page over an object (excluded, string)", async (t) => {
+  let tmpl = await getNewTemplate(
+    "./test/stubs/paged/pagedobjectexcludestring.njk",
+    "./test/stubs/",
+    "./dist"
+  );
+
+  let data = await tmpl.getData();
+  let pages = await tmpl.getTemplates(data);
+  t.is(pages.length, 2);
+
+  t.is(
+    (await pages[0].template.render(pages[0].data)).trim(),
+    "<ol><li>item1</li><li>item2</li><li>item3</li><li>item5</li></ol>"
+  );
+
+  t.is(
+    (await pages[1].template.render(pages[1].data)).trim(),
+    "<ol><li>item6</li><li>item7</li><li>item8</li><li>item9</li></ol>"
+  );
+});
+
 test("Page over an object (filtered, array)", async (t) => {
   let tmpl = await getNewTemplate(
     "./test/stubs/paged/pagedobjectfilterarray.njk",

test/stubs/paged/pagedobjectexcludearray.njk

@@ -0,0 +1,18 @@
+---
+pagination:
+  data: testdata
+  size: 4
+  exclude:
+    - item4
+testdata:
+  item1: itemvalue1
+  item2: itemvalue2
+  item3: itemvalue3
+  item4: itemvalue4
+  item5: itemvalue5
+  item6: itemvalue6
+  item7: itemvalue7
+  item8: itemvalue8
+  item9: itemvalue9
+---
+<ol>{% for item in pagination.items %}<li>{{ item }}</li>{% endfor %}</ol>

test/stubs/paged/pagedobjectexcludestring.njk

@@ -0,0 +1,17 @@
+---
+pagination:
+  data: testdata
+  size: 4
+  exclude: item4
+testdata:
+  item1: itemvalue1
+  item2: itemvalue2
+  item3: itemvalue3
+  item4: itemvalue4
+  item5: itemvalue5
+  item6: itemvalue6
+  item7: itemvalue7
+  item8: itemvalue8
+  item9: itemvalue9
+---
+<ol>{% for item in pagination.items %}<li>{{ item }}</li>{% endfor %}</ol>

test/stubs/paged/pagedobjectincludearray.njk

@@ -0,0 +1,19 @@
+---
+pagination:
+  data: testdata
+  size: 4
+  include:
+    - item3
+    - item4
+testdata:
+  item1: itemvalue1
+  item2: itemvalue2
+  item3: itemvalue3
+  item4: itemvalue4
+  item5: itemvalue5
+  item6: itemvalue6
+  item7: itemvalue7
+  item8: itemvalue8
+  item9: itemvalue9
+---
+<ol>{% for item in pagination.items %}<li>{{ item }}</li>{% endfor %}</ol>

test/stubs/paged/pagedobjectincludeexclude.njk

@@ -0,0 +1,18 @@
+---
+pagination:
+  data: testdata
+  size: 4
+  include: item4
+  exclude: item5
+testdata:
+  item1: itemvalue1
+  item2: itemvalue2
+  item3: itemvalue3
+  item4: itemvalue4
+  item5: itemvalue5
+  item6: itemvalue6
+  item7: itemvalue7
+  item8: itemvalue8
+  item9: itemvalue9
+---
+<ol>{% for item in pagination.items %}<li>{{ item }}</li>{% endfor %}</ol>

test/stubs/paged/pagedobjectincludestring.njk

@@ -0,0 +1,17 @@
+---
+pagination:
+  data: testdata
+  size: 4
+  include: item4
+testdata:
+  item1: itemvalue1
+  item2: itemvalue2
+  item3: itemvalue3
+  item4: itemvalue4
+  item5: itemvalue5
+  item6: itemvalue6
+  item7: itemvalue7
+  item8: itemvalue8
+  item9: itemvalue9
+---
+<ol>{% for item in pagination.items %}<li>{{ item }}</li>{% endfor %}</ol>