feat: add improved prune() function

docs/README.md

@@ -22,5 +22,6 @@ in the future, but also provides a place for less general, yet useful utilities.
 * [inspect](inspect.md)
 * [jsonpath](jsonpath.md)
 * [number](number.md)
+* [reflect](reflect.md)
 * [string](string.md)
 * [url](url.md)

docs/reflect.md

@@ -0,0 +1,25 @@
+---
+permalink: /reflect/
+---
+
+# reflect
+
+```jsonnet
+local reflect = import "github.com/jsonnet-libs/xtd/reflect.libsonnet"
+```
+
+`reflect` implements helper functions for processing json data.
+
+## Index
+
+* [`fn prune(a, recurse=true, only_null=false)`](#fn-prune)
+
+## Fields
+
+### fn prune
+
+```ts
+prune(a, recurse=true, only_null=false)
+```
+
+`prune` works the same as `std.prune` but with the options to disable recursion and only pruning `null` values.

main.libsonnet

@@ -20,6 +20,7 @@ local d = import 'github.com/jsonnet-libs/docsonnet/doc-util/main.libsonnet';
   inspect: (import './inspect.libsonnet'),
   jsonpath: (import './jsonpath.libsonnet'),
   number: (import './number.libsonnet'),
+  reflect: (import './reflect.libsonnet'),
   string: (import './string.libsonnet'),
   url: (import './url.libsonnet'),
 }

reflect.libsonnet

@@ -0,0 +1,47 @@
+local d = import 'github.com/jsonnet-libs/docsonnet/doc-util/main.libsonnet';
+
+{
+  '#': d.pkg(
+    name='reflect',
+    url='github.com/jsonnet-libs/xtd/reflect.libsonnet',
+    help='`reflect` implements helper functions for processing json data.',
+  ),
+
+  '#prune':: d.fn(
+    '`prune` works the same as `std.prune` but with the options to disable recursion and only pruning `null` values.',
+    [
+      d.arg('a', d.T.any),
+      d.arg('recurse', d.T.bool, default=true),
+      d.arg('only_null', d.T.bool, default=false),
+    ]
+  ),
+  prune(a, recurse=true, only_null=false)::
+    local isContent(b) =
+      if b == null
+      then false
+      else if only_null
+      then true
+      else if std.isArray(b)
+      then std.length(b) > 0
+      else if std.isObject(b)
+      then std.length(b) > 0
+      else true;
+    local doRecursion(x) =
+      if recurse
+      then self.prune(x, only_null=only_null)
+      else x;
+    if std.isArray(a)
+    then [
+      doRecursion(x)
+      for x in a
+      if isContent(doRecursion(x))
+    ]
+    else if std.isObject(a)
+    then {
+      [x]: doRecursion(a[x])
+      for x in std.objectFields(a)
+      if isContent(doRecursion(a[x]))
+    }
+    else
+      a,
+}

test/reflect_test.jsonnet

@@ -0,0 +1,42 @@
+local reflect = import '../reflect.libsonnet';
+local test = import 'github.com/jsonnet-libs/testonnet/main.libsonnet';
+
+local obj = {
+  a: {},
+  b: null,
+  c: {
+    d: {},
+    e: null,
+  },
+};
+
+test.new(std.thisFile)
+
++ test.case.new(
+  name='prune: vanilla',
+  test=test.expect.eq(
+    actual=reflect.prune(obj),  // true/false
+    expected={},
+  )
+)
++ test.case.new(
+  name='prune: no recurse',
+  test=test.expect.eq(
+    actual=reflect.prune(obj, recurse=false),  // false/false
+    expected={ c: { d: {}, e: null } },
+  )
+)
++ test.case.new(
+  name='prune: only null',
+  test=test.expect.eq(
+    actual=reflect.prune(obj, only_null=true),  // true/true
+    expected={ a: {}, c: { d: {} } },
+  )
+)
++ test.case.new(
+  name='prune: no recurse && only null',
+  test=test.expect.eq(
+    actual=reflect.prune(obj, recurse=false, only_null=true),  // false/true
+    expected={ a: {}, c: { d: {}, e: null } },
+  )
+)