Add Purge Null And Undefined Values From Object as a JavaScript TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1229 TILs and counting..._
+_1230 TILs and counting..._
 
 ---
 
@@ -431,6 +431,7 @@ _1229 TILs and counting..._
 - [Object Initialization With Shorthand Property Names](javascript/object-initialization-with-shorthand-property-names.md)
 - [Obtain Undefined Value With The Void Operator](javascript/obtain-undefined-value-with-the-void-operator.md)
 - [Parse A Date From A Timestamp](javascript/parse-a-date-from-a-timestamp.md)
+- [Purge Null And Undefined Values From Object](javascript/purge-null-and-undefined-values-from-object.md)
 - [Random Cannot Be Seeded](javascript/random-cannot-be-seeded.md)
 - [Reach Into An Object For Nested Data With Get](javascript/reach-into-an-object-for-nested-data-with-get.md)
 - [Render An Array Of Elements With React 16](javascript/render-an-array-of-elements-with-react-16.md)

javascript/purge-null-and-undefined-values-from-object.md

@@ -0,0 +1,40 @@
+# Purge Null And Undefined Values From Object
+
+The low-level utilities provided by [`lodash`](https://lodash.com/) offer a
+couple ways to remove all the `null` and `undefined` values from an object.
+
+First, here is an object that I want to _compact_ by removing all `nil` (`null`
+and `undefined`) values.
+
+```javascript
+const data = {
+  hello: 'world',
+  list: [1,2,3],
+  status: undefined,
+  published_at: null,
+  points: 0
+}
+```
+
+One method of doing this is with the [`_.pickBy`
+function](https://lodash.com/docs/4.17.15#pickBy).
+
+```javascript
+> _.pickBy(data)
+//=> { hello: 'world', list: [1,2,3] }
+```
+
+Because it defaults to picking _truthy_ values, the `points: 0` is also going
+to be stripped out.
+
+Another method which allows us to more directly target just `null` and
+`undefined` uses [`_.omitBy`](https://lodash.com/docs/4.17.15#omitBy) and
+[`_.isNil`](https://lodash.com/docs/4.17.15#isNil).
+
+```javascript
+> _.omitBy(data, _.isNil)
+//=> { hello: 'world', list: [1,2,3], points: 0 }
+```
+
+Notice this approach only removes the `null` and `undefined` key-value pairs.
+The `points: 0` is left in.