From c8e0b77bbd8e845b337d7c19b6eca72c4bac569f Mon Sep 17 00:00:00 2001
From: Michele Cereda <cereda.michele@gmail.com>
Date: Sat, 2 Mar 2024 01:24:18 +0100
Subject: [PATCH] feat(kb/jq): filter to delete all null values

---
 knowledge base/jq.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/knowledge base/jq.md b/knowledge base/jq.md
index b354cc5..ccfe59c 100644
--- a/knowledge base/jq.md	
+++ b/knowledge base/jq.md	
@@ -31,6 +31,10 @@ jq 'del(.country, .number, .language)' …
 jq 'del(.[0,1,2])' …
 jq 'del(.[0:3])' …
 
+# Remove all null values.
+jq 'del(..|nulls)' …
+jq 'del(recurse(.[]?;true)|select(. == null))' …
+
 # Print objects as 'key [space] "value"' pairs.
 jq -r 'to_entries[] | "\(.key) \"\(.value)\""' 'file.json'
 
@@ -112,6 +116,7 @@ All the references in the [further readings] section, plus the following:
 - [Change multiple values at once]
 - [jq Select range]
 - [Deleting multiple keys at once with jq]
+- [Remove all null values]
 
 <!--
   References
@@ -125,4 +130,5 @@ All the references in the [further readings] section, plus the following:
 [deleting multiple keys at once with jq]: https://stackoverflow.com/questions/36227245/deleting-multiple-keys-at-once-with-jq
 [filter objects list with regex]: https://til.hashrocket.com/posts/uv0bjiokwk-use-jq-to-filter-objects-list-with-regex
 [jq select range]: https://stackoverflow.com/questions/45548604/jq-select-range
+[remove all null values]: https://stackoverflow.com/questions/39500608/remove-all-null-values
 [select multiple conditions]: https://stackoverflow.com/questions/33057420/jq-select-multiple-conditions#33059058