feat: std.flattenDeepArray Concatenate an array containing values and arrays into a single flattened array. (#1082)

* std.flattenDeepArray recursively flattens multiple arrays

Author: bitmaybewise

doc/_stdlib_gen/stdlib-content.jsonnet

@@ -1278,6 +1278,20 @@ local html = import 'html.libsonnet';
             },
           ],
         },
+        {
+          name: 'flattenDeepArray',
+          params: ['value'],
+          availableSince: 'upcoming',
+          description: |||
+            Concatenate an array containing values and arrays into a single flattened array.
+          |||,
+          examples: [
+            {
+              input: 'std.flattenDeepArray([[1, 2], [], [3, [4]], [[5, 6, [null]], [7, 8]]])',
+              output: std.flattenDeepArray([[1, 2], [], [3, [4]], [[5, 6, [null]], [7, 8]]]),
+            },
+          ],
+        },
         {
           name: 'reverse',
           params: ['arrs'],

stdlib/std.jsonnet

@@ -865,6 +865,12 @@ limitations under the License.
   flattenArrays(arrs)::
     std.foldl(function(a, b) a + b, arrs, []),
 
+  flattenDeepArray(value)::
+    if std.isArray(value) then
+      [y for x in value for y in std.flattenDeepArray(x)]
+    else
+      [value],
+
   manifestIni(ini)::
     local body_lines(body) =
       std.join([], [

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.flattenDeepArray([]), []) &&
+std.assertEqual(std.flattenDeepArray([1, 2, 3]), [1, 2, 3]) &&
+std.assertEqual(std.flattenDeepArray([1, [2, 3]]), [1, 2, 3]) &&
+std.assertEqual(std.flattenDeepArray([[1], [2, 3], [[null]]]), [1, 2, 3, null]) &&
+
 std.assertEqual(
   std.manifestIni({
     main: { a: '1', b: '2' },