JS dynamic bit string

3 files changed, 59 insertions, 32 deletions

diff --git a/src/gleam/dynamic.gleam b/src/gleam/dynamic.gleam
index 86d1b6e..903341a 100644
--- a/src/gleam/dynamic.gleam
+++ b/src/gleam/dynamic.gleam
@@ -60,22 +60,31 @@ if javascript {
     "../gleam_stdlib.js" "identity"
 }
 
+/// Checks to see whether a Dynamic value is a bit_string, and return the bit_string if
+/// it is.
+///
+/// ## Examples
+///
+///    > bit_string(from("Hello")) == bit_string.from_string("Hello")
+///    True
+///
+///    > bit_string(from(123))
+///    Error(DecodeError(expected: "BitString", found: "Int"))
+///
+pub fn bit_string(from data: Dynamic) -> Result(BitString, DecodeError) {
+  decode_bit_string(data)
+}
+
 if erlang {
-  /// Checks to see whether a Dynamic value is a bit_string, and return the bit_string if
-  /// it is.
-  ///
-  /// ## Examples
-  ///
-  ///    > bit_string(from("Hello")) == bit_string.from_string("Hello")
-  ///    True
-  ///
-  ///    > bit_string(from(123))
-  ///    Error(DecodeError(expected: "BitString", found: "Int"))
-  ///
-  pub external fn bit_string(from: Dynamic) -> Result(BitString, DecodeError) =
+  external fn decode_bit_string(Dynamic) -> Result(BitString, DecodeError) =
     "gleam_stdlib" "decode_bit_string"
 }
 
+if javascript {
+  external fn decode_bit_string(Dynamic) -> Result(BitString, DecodeError) =
+    "../gleam_stdlib.js" "decode_bit_string"
+}
+
 /// Checks to see whether a Dynamic value is a string, and return the string if
 /// it is.
 ///
diff --git a/src/gleam_stdlib.js b/src/gleam_stdlib.js
index b8feecf..0982f62 100644
--- a/src/gleam_stdlib.js
+++ b/src/gleam_stdlib.js
@@ -476,6 +476,8 @@ function classify_dynamic(data) {
     return "List";
   } else if (Number.isInteger(data)) {
     return "Int";
+  } else if (BitString.isBitString(data)) {
+    return "BitString";
   } else if (typeof data === "number") {
     return "Float";
   } else {
@@ -501,6 +503,13 @@ export function decode_int(data) {
 export function decode_float(data) {
   return typeof data === "number" ? new Ok(data) : decoder_error("Float", data);
 }
+
 export function decode_bool(data) {
   return typeof data === "boolean" ? new Ok(data) : decoder_error("Bool", data);
 }
+
+export function decode_bit_string(data) {
+  return BitString.isBitString(data)
+    ? new Ok(data)
+    : decoder_error("BitString", data);
+}
diff --git a/test/gleam/dynamic_test.gleam b/test/gleam/dynamic_test.gleam
index 3229e3d..c65f98c 100644
--- a/test/gleam/dynamic_test.gleam
+++ b/test/gleam/dynamic_test.gleam
@@ -1,38 +1,42 @@
 import gleam/should
 import gleam/dynamic.{DecodeError}
+import gleam/bit_string
 
 if erlang {
-  import gleam/bit_string
   import gleam/list
   import gleam/result
   import gleam/map
   import gleam/option.{None, Some}
+}
 
-  pub fn bit_string_test() {
-    ""
-    |> dynamic.from
-    |> dynamic.bit_string
-    |> should.equal(Ok(<<"":utf8>>))
+pub fn bit_string_test() {
+  <<>>
+  |> dynamic.from
+  |> dynamic.bit_string
+  |> should.equal(Ok(<<>>))
 
-    "Hello"
-    |> dynamic.from
-    |> dynamic.bit_string
-    |> should.equal(Ok(<<"Hello":utf8>>))
+  <<"Hello":utf8>>
+  |> dynamic.from
+  |> dynamic.bit_string
+  |> should.equal(Ok(<<"Hello":utf8>>))
 
-    <<65535:16>>
-    |> dynamic.from
-    |> dynamic.bit_string
-    |> should.equal(Ok(<<65535:16>>))
+  1
+  |> dynamic.from
+  |> dynamic.bit_string
+  |> should.equal(Error(DecodeError(expected: "BitString", found: "Int")))
 
-    1
-    |> dynamic.from
-    |> dynamic.bit_string
-    |> should.equal(Error(DecodeError(expected: "BitString", found: "Int")))
+  []
+  |> dynamic.from
+  |> dynamic.bit_string
+  |> should.equal(Error(DecodeError(expected: "BitString", found: "List")))
+}
 
-    []
+if erlang {
+  pub fn bit_string_erlang_test() {
+    <<65535:16>>
     |> dynamic.from
     |> dynamic.bit_string
-    |> should.equal(Error(DecodeError(expected: "BitString", found: "List")))
+    |> should.equal(Ok(<<65535:16>>))
   }
 }
 
@@ -82,6 +86,11 @@ pub fn int_test() {
   |> dynamic.from
   |> dynamic.int
   |> should.equal(Error(DecodeError(expected: "Int", found: "List")))
+
+  <<1>>
+  |> dynamic.from
+  |> dynamic.int
+  |> should.equal(Error(DecodeError(expected: "Int", found: "BitString")))
 }
 
 pub fn float_test() {