Add Numbers Are Empty as a javascript til

javascript/numbers-are-empty.md

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+# Numbers Are Empty
+
+The [`lodash`](https://lodash.com/) project comes with a ton of handy
+JavaScript utilities including the
+[`_.isEmpty()`](https://lodash.com/docs#isEmpty) function. This is great for
+checking if Arrays, Objects, and Strings are _empty_. The following is how
+this function is defined in the docs:
+
+> Checks if value is an empty collection or object. A value is considered
+> empty if it's an arguments object, array, string, or jQuery-like
+> collection with a length of 0 or has no own enumerable properties.
+
+Having not examined this definition too closely and because I primarily
+write Rails code from day to day, I conflated `_.isEmpty()` with the
+`#blank?` method provided by Rails' `ActiveSupport`. This holds true for the
+most part, but quickly defies expectations when it comes to numbers.
+
+```javascript
+> _.isEmpty(1)
+// true
+```