Element requires type

2 files changed, 21 insertions, 14 deletions

diff --git a/src/gleam/dynamic.gleam b/src/gleam/dynamic.gleam
index fa1b69e..82cfa2f 100644
--- a/src/gleam/dynamic.gleam
+++ b/src/gleam/dynamic.gleam
@@ -421,11 +421,12 @@ if javascript {
 ///
 pub fn element(
   from data: Dynamic,
-  get index: Int,
-) -> Result(Dynamic, DecodeError) {
+  at index: Int,
+  of inner_type: Decoder(t),
+) -> Result(t, DecodeError) {
   try tuple = decode_tuple(data)
   let size = tuple_size(tuple)
-  case index >= 0 {
+  try data = case index >= 0 {
     True ->
       case index < size {
         True -> tuple_get(tuple, index)
@@ -437,6 +438,7 @@ pub fn element(
         False -> at_least_decode_tuple_error(int.absolute_value(index), data)
       }
   }
+  inner_type(data)
 }
 
 fn exact_decode_tuple_error(size: Int, data: Dynamic) -> Result(a, DecodeError) {
diff --git a/test/gleam/dynamic_test.gleam b/test/gleam/dynamic_test.gleam
index 62bab63..c79bc75 100644
--- a/test/gleam/dynamic_test.gleam
+++ b/test/gleam/dynamic_test.gleam
@@ -289,17 +289,22 @@ pub fn element_test() {
 
   ok_one_tuple
   |> dynamic.from
-  |> dynamic.element(0)
-  |> should.equal(Ok(dynamic.from("ok")))
+  |> dynamic.element(0, dynamic.string)
+  |> should.equal(Ok("ok"))
 
   ok_one_tuple
   |> dynamic.from
-  |> dynamic.element(1)
-  |> should.equal(Ok(dynamic.from(1)))
+  |> dynamic.element(1, dynamic.int)
+  |> should.equal(Ok(1))
+
+  ok_one_tuple
+  |> dynamic.from
+  |> dynamic.element(1, dynamic.string)
+  |> should.equal(Error(DecodeError(expected: "String", found: "Int")))
 
   ok_one_tuple
   |> dynamic.from
-  |> dynamic.element(2)
+  |> dynamic.element(2, dynamic.int)
   |> should.equal(Error(DecodeError(
     expected: "Tuple of at least 3 elements",
     found: "Tuple of 2 elements",
@@ -307,12 +312,12 @@ pub fn element_test() {
 
   ok_one_tuple
   |> dynamic.from
-  |> dynamic.element(-1)
-  |> should.equal(Ok(dynamic.from(1)))
+  |> dynamic.element(-1, dynamic.int)
+  |> should.equal(Ok(1))
 
   ok_one_tuple
   |> dynamic.from
-  |> dynamic.element(-3)
+  |> dynamic.element(-3, dynamic.int)
   |> should.equal(Error(DecodeError(
     expected: "Tuple of at least 3 elements",
     found: "Tuple of 2 elements",
@@ -320,18 +325,18 @@ pub fn element_test() {
 
   1
   |> dynamic.from
-  |> dynamic.element(-3)
+  |> dynamic.element(-3, dynamic.int)
   |> should.equal(Error(DecodeError(expected: "Tuple", found: "Int")))
 
   1
   |> dynamic.from
-  |> dynamic.element(0)
+  |> dynamic.element(0, dynamic.int)
   |> should.equal(Error(DecodeError(expected: "Tuple", found: "Int")))
 
   map.new()
   |> map.insert(1, "ok")
   |> dynamic.from
-  |> dynamic.element(0)
+  |> dynamic.element(0, dynamic.int)
   |> should.equal(Error(DecodeError(expected: "Tuple", found: "Map")))
 }