From 336ff9574a240dea8fe109161581981796c679b0 Mon Sep 17 00:00:00 2001
From: Deep Goel <deepgoel@google.com>
Date: Sun, 13 Aug 2023 17:10:51 +0530
Subject: [PATCH] Implementing the GroupBy

---
 doc/_stdlib_gen/stdlib-content.jsonnet | 10 ++++++++++
 stdlib/std.jsonnet                     |  9 +++++++++
 test_suite/stdlib.jsonnet              |  3 ++-
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/doc/_stdlib_gen/stdlib-content.jsonnet b/doc/_stdlib_gen/stdlib-content.jsonnet
index dd662773d..d10358f44 100644
--- a/doc/_stdlib_gen/stdlib-content.jsonnet
+++ b/doc/_stdlib_gen/stdlib-content.jsonnet
@@ -1432,6 +1432,16 @@ local html = import 'html.libsonnet';
             |||,
           ]),
         },
+        {
+          name: 'groupBy',
+          params: ['arr', 'keyF', 'onEmpty'],
+          availableSince: 'upcoming',
+          description: html.paragraphs([
+            |||
+              Return an object composed of keys generated from the results of running each element of  <code>arr</code> through <code>function</code>.
+            |||,
+          ]),
+        },
       ],
     },
     {
diff --git a/stdlib/std.jsonnet b/stdlib/std.jsonnet
index c861a4aec..bf9f7911f 100644
--- a/stdlib/std.jsonnet
+++ b/stdlib/std.jsonnet
@@ -1741,6 +1741,15 @@ limitations under the License.
           a;
       std.foldl(maxFn, arr, maxVal),
 
+  groupBy(arr, keyF=id)::
+    local foldf(o, e, f) = 
+    local k = std.toString(f(e));
+    if std.objectHas(o, k) then
+    c + {[k]: o[k] + [e]}
+    else
+    o + {[k]: [e]};
+    std.foldl(function(o, e) foldf(o, e, f), arr, {});
+
   xor(x, y):: x != y,
 
   xnor(x, y):: x == y,
diff --git a/test_suite/stdlib.jsonnet b/test_suite/stdlib.jsonnet
index e3b290e06..d9126c017 100644
--- a/test_suite/stdlib.jsonnet
+++ b/test_suite/stdlib.jsonnet
@@ -1560,6 +1560,7 @@ std.assertEqual(std.maxArray([1, 2, 3]), 3) &&
 std.assertEqual(std.maxArray(['1', '2', '3']), '3') &&
 std.assertEqual(std.maxArray(['a', 'x', 'z']), 'z') &&
 
+std.assertEqual(std.groupBy([1, 1.5, 2, 3], std.floor), { '1': [1, 1.5], '2': [2], '3': [3] }) &&
 
 std.assertEqual(std.xor(true, false), true) &&
 std.assertEqual(std.xor(true, true), false) &&
@@ -1597,6 +1598,6 @@ std.assertEqual(std.trim('already trimmed string'), 'already trimmed string') &&
 std.assertEqual(std.trim('    string with spaces on both ends     '), 'string with spaces on both ends') &&
 std.assertEqual(std.trim('string with newline character at end\n'), 'string with newline character at end') &&
 std.assertEqual(std.trim('string with tabs at end\t\t'), 'string with tabs at end') &&
-std.assertEqual(std.trim('string with other special whitespaces at end\f\r\u0085\u00A0'), 'string with carriage return at end') &&
+std.assertEqual(std.trim('string with other special whitespaces at end\f\r\u0085 '), 'string with carriage return at end') &&
 
 true