feat: implement std.minArray (#1074)

* Add std.minArray in standard library

Author: deepgoel17

doc/_stdlib_gen/stdlib-content.jsonnet

@@ -1421,6 +1421,14 @@ local html = import 'html.libsonnet';
             |||,
           ]),
         },
+        {
+          name: 'minArray',
+          params: ['arr', 'keyF', 'onEmpty'],
+          availableSince: 'upcoming',
+          description: html.paragraphs([
+            |||
+              Return the min of all element in <code>arr</code>.
+        },
         {
           name: 'contains',
           params: ['arr', 'elem'],

stdlib/std.jsonnet

@@ -1703,6 +1703,18 @@ limitations under the License.
 
   sum(arr):: std.foldl(function(a, b) a + b, arr, 0),
 
+  minArray(arr, keyF=id, onEmpty=error 'Expected at least one element in array. Got none')::
+    if std.length(arr) == 0 then
+      onEmpty
+    else
+      local minVal = arr[0];
+      local minFn(a, b) =
+        if std.__compare(keyF(a), keyF(b)) > 0 then
+          b
+        else
+          a;
+      std.foldl(minFn, arr, minVal),
+
   xor(x, y):: x != y,
 
   xnor(x, y):: x == y,

test_suite/stdlib.jsonnet

@@ -1544,6 +1544,9 @@ std.assertEqual(std.all([]), true) &&
 
 std.assertEqual(std.sum([1, 2, 3]), 6) &&
 
+std.assertEqual(std.minArray([1, 2, 3]), 1) &&
+std.assertEqual(std.minArray(['1', '2', '3']), '1') &&
+
 std.assertEqual(std.xor(true, false), true) &&
 std.assertEqual(std.xor(true, true), false) &&