From 9398f911c1f2a480bda60511758825e595ce279b Mon Sep 17 00:00:00 2001
From: Hercules Merscher <hlmerscher@gmail.com>
Date: Sun, 7 May 2023 13:19:49 +0200
Subject: [PATCH] std.compactArray recursively flattens multiple arrays

---
 doc/_stdlib_gen/stdlib-content.jsonnet | 14 ++++++++++++++
 stdlib/std.jsonnet                     | 10 ++++++++++
 test_suite/stdlib.jsonnet              |  5 +++++
 3 files changed, 29 insertions(+)

diff --git a/doc/_stdlib_gen/stdlib-content.jsonnet b/doc/_stdlib_gen/stdlib-content.jsonnet
index 40de10df..b5b0c580 100644
--- a/doc/_stdlib_gen/stdlib-content.jsonnet
+++ b/doc/_stdlib_gen/stdlib-content.jsonnet
@@ -1349,6 +1349,20 @@ local html = import 'html.libsonnet';
             },
           ],
         },
+        {
+          name: 'compactArrays',
+          params: ['arrs'],
+          availableSince: 'upcoming',
+          description: |||
+            Concatenate an array of arrays into a single flattened array, removing null values.
+          |||,
+          examples: [
+            {
+              input: 'std.compactArrays([[1, 2], [], [3, [4]], [[5, 6, [null]], [7, 8]]])',
+              output: std.compactArrays([1, 2, 3, 4, 5, 6, 7, 8]),
+            },
+          ],
+        },
         {
           name: 'reverse',
           params: ['arrs'],
diff --git a/stdlib/std.jsonnet b/stdlib/std.jsonnet
index 160dd7eb..a96d7bd5 100644
--- a/stdlib/std.jsonnet
+++ b/stdlib/std.jsonnet
@@ -865,6 +865,16 @@ limitations under the License.
   flattenArrays(arrs)::
     std.foldl(function(a, b) a + b, arrs, []),
 
+  compactArray(arrs)::
+    local foldable = function(accumulator, value)
+      if std.isArray(value) then
+        accumulator + std.compactArray(value)
+      else if value == null then
+        accumulator
+      else
+        accumulator + [value];
+    std.foldl(foldable, arrs, []),
+
   manifestIni(ini)::
     local body_lines(body) =
       std.join([], [
diff --git a/test_suite/stdlib.jsonnet b/test_suite/stdlib.jsonnet
index 18639924..026326c0 100644
--- a/test_suite/stdlib.jsonnet
+++ b/test_suite/stdlib.jsonnet
@@ -313,6 +313,11 @@ std.assertEqual(std.lines(['a', null, 'b']), 'a\nb\n') &&
 
 std.assertEqual(std.flattenArrays([[1, 2, 3], [4, 5, 6], []]), [1, 2, 3, 4, 5, 6]) &&
 
+std.assertEqual(std.compactArray([]), []) &&
+std.assertEqual(std.compactArray([1, 2, 3]), [1, 2, 3]) &&
+std.assertEqual(std.compactArray([1, [2, 3]]), [1, 2, 3]) &&
+std.assertEqual(std.compactArray([[1], [2, 3], []]), [1, 2, 3]) &&
+
 std.assertEqual(
   std.manifestIni({
     main: { a: '1', b: '2' },