Add Truthiness of Integer Arrays as a javascript til.

README.md

@@ -38,6 +38,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 ## javascript
 
 - [Character Codes from Keyboard Listeners](javascript/character-codes-from-keyboard-listeners.md)
+- [Truthiness of Integer Arrays](javascript/truthiness-of-integer-arrays.md)
 
 ### postgres
 

javascript/truthiness-of-integer-arrays.md

@@ -0,0 +1,28 @@
+# Truthiness of Integer Arrays
+
+We can consider the truthiness of `[1]` as follows:
+
+```javascript
+> [1] == true
+=> true
+> Boolean(true)
+=> true
+> Boolean([1])
+=> true
+```
+
+We can consider the truthiness of `[0]` as follows:
+
+```javascript
+> [0] == false
+=> true
+> Boolean(false)
+=> false
+> Boolean([0])
+=> true
+```
+
+The truthiness of `[0]` does not seem to be consistent.
+
+See this [JavaScript Equality Table](https://dorey.github.io/JavaScript-Equality-Table/)
+for more details.