firstSome infix operator

README.md

@@ -149,6 +149,27 @@ let lastEqual = (xs, ys) =>
   Some(Util.eq) <*> RList.last(xs) <*> RList.last(ys) |> Option.default(false);
 ```
 
+### Translating JS Idioms
+
+### Or chains
+
+Take the following example in Javascript:
+
+```Javascript
+let x = a || b || c || d;
+```
+
+We can't translate that directly to Reason, because there is no `null` or `undefined` in Reason.
+The closest approximation would be `option`, in which we can string together `Some` and `None`
+to get the first one that is `Some`.
+
+There is a helper function called `firstSome` and its infix variation `|?` that do exactly this.
+
+```Reason
+/* a, b, and c are all options, but d is not */
+let x = a |? b |? c |> default(d);
+```
+
 Reference
 --------------------------------------------------------------------------------
 
@@ -161,3 +182,4 @@ Reference
 - `||>`: Point-free Function Pipe
 - `-<<`: Lens Compose
 - `>>-`: Lens Pipe
+- `|?`: Optional Or

src/Option.re

@@ -77,4 +77,5 @@ module Infix = {
   let (>>=) = (>>=);
   let (<$>) = (<$>);
   let (<*>) = (<*>);
+  let (|?) = firstSome;
 };

src/Option.rei

@@ -38,4 +38,5 @@ module Infix: {
   let (>>=): (option('a), 'a => option('b)) => option('b);
   let (<$>): (option('a), 'a => 'b) => option('b);
   let (<*>): (option(('a => 'b)), option('a)) => option('b);
+  let (|?): (option('a), option('a)) => option('a);
 };