feat(array): add findMap

Author: glennsl

src/Core__Array.mjs

@@ -106,6 +106,22 @@ function flatMap(a, f) {
   return Caml_splice_call.spliceObjApply([], "concat", [a.map(f)]);
 }
 
+function findMap(arr, f) {
+  var _i = 0;
+  while(true) {
+    var i = _i;
+    if (i === arr.length) {
+      return ;
+    }
+    var r = Curry._1(f, arr[i]);
+    if (r !== undefined) {
+      return r;
+    }
+    _i = i + 1 | 0;
+    continue ;
+  };
+}
+
 export {
   indexOfOpt ,
   lastIndexOfOpt ,
@@ -118,5 +134,6 @@ export {
   shuffle ,
   shuffleInPlace ,
   flatMap ,
+  findMap ,
 }
 /* No side effect */

src/Core__Array.res

@@ -197,4 +197,18 @@ let filterMap = (a, f) => filterMapU(a, (. a) => f(a))
 // TODO: Change this implementation?
 let flatMap = (a, f) => []->concatMany(map(a, f))
 
+let findMap = (arr, f) => {
+  let rec loop = i =>
+    if i == arr->length {
+      None
+    } else {
+      switch f(getUnsafe(arr, i)) {
+      | None => loop(i + 1)
+      | Some(_) as r => r
+      }
+    }
+
+  loop(0)
+}
+
 @send external at: (array<'a>, int) => option<'a> = "at"

src/Core__Array.resi

@@ -103,7 +103,7 @@ let filterMap: (array<'a>, 'a => option<'b>) => array<'b>
 let shuffle: array<'a> => array<'a>
 let shuffleInPlace: array<'a> => unit
 let flatMap: (array<'a>, 'a => array<'b>) => array<'b>
-
+let findMap: (array<'a>, 'a => option<'b>) => option<'b>
 
 /** 
   `at(array, index)`
@@ -120,4 +120,5 @@ let flatMap: (array<'a>, 'a => array<'b>) => array<'b>
   ["a", "b", "c"]->Array.at(-4) // None
   ```
 */
-@send external at: (array<'a>, int) => option<'a> = "at"
+@send
+external at: (array<'a>, int) => option<'a> = "at"