Make iterator.any/all TCO eligible in JavaScript

Fixes #427

2 files changed, 24 insertions, 4 deletions

diff --git a/src/gleam/iterator.gleam b/src/gleam/iterator.gleam
index 89d50a8..1486ae3 100644
--- a/src/gleam/iterator.gleam
+++ b/src/gleam/iterator.gleam
@@ -995,7 +995,11 @@ fn do_any(
 ) -> Bool {
   case continuation() {
     Stop -> False
-    Continue(e, next) -> predicate(e) || do_any(next, predicate)
+    Continue(e, next) ->
+      case predicate(e) {
+        True -> True
+        False -> do_any(next, predicate)
+      }
   }
 }
 
@@ -1037,7 +1041,11 @@ fn do_all(
 ) -> Bool {
   case continuation() {
     Stop -> True
-    Continue(e, next) -> predicate(e) && do_all(next, predicate)
+    Continue(e, next) ->
+      case predicate(e) {
+        True -> do_all(next, predicate)
+        False -> False
+      }
   }
 }
 
@@ -1391,10 +1399,10 @@ fn do_length(over continuation: fn() -> Action(e), with length: Int) -> Int {
 /// Counts the number of elements in the given iterator.
 ///
 /// This function has to traverse the entire iterator to count its elements,
-/// so it runs in linear time. 
+/// so it runs in linear time.
 ///
 /// ## Examples
-/// 
+///
 /// ```gleam
 /// > empty() |> length
 /// 0
diff --git a/test/gleam/iterator_test.gleam b/test/gleam/iterator_test.gleam
index 9c98c9d..81c790e 100644
--- a/test/gleam/iterator_test.gleam
+++ b/test/gleam/iterator_test.gleam
@@ -406,6 +406,12 @@ pub fn any_test() {
   iterator.from_list([1, 3, 5, 7, 9])
   |> iterator.any(satisfying: fn(n) { n % 2 == 0 })
   |> should.be_false
+
+  // TCO test
+  iterator.repeat(1)
+  |> iterator.take(1_000_000)
+  |> iterator.any(satisfying: fn(n) { n % 2 == 0 })
+  |> should.be_false
 }
 
 pub fn all_test() {
@@ -420,6 +426,12 @@ pub fn all_test() {
   iterator.from_list([2, 4, 5, 8])
   |> iterator.all(satisfying: fn(n) { n % 2 == 0 })
   |> should.be_false
+
+  // TCO test
+  iterator.repeat(0)
+  |> iterator.take(1_000_000)
+  |> iterator.all(satisfying: fn(n) { n % 2 == 0 })
+  |> should.be_true
 }
 
 pub fn group_test() {