fix: RegExp.Result.t should be an array of options

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Next version
 
+- BREAKING: Fixes the type of `RegExp.Result.t` to be `array<option<string>>` instead of `array<string>`. https://github.com/rescript-association/rescript-core/pull/234.
+
 ## 1.4.0
 
 - Add `RegExp.setLastIndex` function. https://github.com/rescript-association/rescript-core/pull/219

src/Core__RegExp.res

@@ -1,7 +1,7 @@
 type t = Js.Re.t
 
 module Result = {
-  type t = array<string>
+  type t = array<option<string>>
   @get_index external fullMatch: (t, @as(0) _) => string = ""
   @send external matches: (t, @as(1) _) => array<string> = "slice"
   @get external index: t => int = "index"

src/Core__RegExp.resi

@@ -13,7 +13,7 @@ module Result: {
   /**
   Type representing the result of a `RegExp` execution.
   */
-  type t = array<string>
+  type t = array<option<string>>
 
   /**
   `fullMatch(regExpResult)` returns the full string that matched in this result.

src/Core__String.resi

@@ -429,10 +429,11 @@ See [`String.match`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Ref
 ## Examples
 
 ```rescript
-String.match("The better bats", %re("/b[aeiou]t/")) == Some(["bet"])
-String.match("The better bats", %re("/b[aeiou]t/g")) == Some(["bet", "bat"])
+String.match("The better bats", %re("/b[aeiou]t/")) == Some([Some("bet")])
+String.match("The better bats", %re("/b[aeiou]t/g")) == Some([Some("bet"), Some("bat")])
 String.match("Today is 2018-04-05.", %re("/(\d+)-(\d+)-(\d+)/")) ==
-  Some(["2018-04-05", "2018", "04", "05"])
+  Some([Some("2018-04-05"), Some("2018"), Some("04"), Some("05")])
+String.match("The optional example", %re("/(foo)?(example)/")) == Some([Some("example"), None, Some("example")])
 String.match("The large container.", %re("/b[aeiou]g/")) == None
 ```
 */