JS float functions

3 files changed, 146 insertions, 97 deletions

diff --git a/src/gleam/float.gleam b/src/gleam/float.gleam
index 8fdb79e..1191ac1 100644
--- a/src/gleam/float.gleam
+++ b/src/gleam/float.gleam
@@ -97,40 +97,80 @@ pub fn max(a: Float, b: Float) -> Float {
   }
 }
 
+/// Rounds the value to the next highest whole number as a float.
+///
+/// ## Examples
+///
+///    > ceiling(2.3)
+///    3.0
+///
+pub fn ceiling(float: Float) -> Float {
+  do_ceiling(float)
+}
+
 if erlang {
-  /// Rounds the value to the next highest whole number as a float.
-  ///
-  /// ## Examples
-  ///
-  ///    > ceiling(2.3)
-  ///    3.0
-  ///
-  pub external fn ceiling(Float) -> Float =
+  external fn do_ceiling(Float) -> Float =
     "math" "ceil"
+}
 
-  /// Rounds the value to the next lowest whole number as a float.
-  ///
-  /// ## Examples
-  ///
-  ///    > floor(2.3)
-  ///    2.0
-  ///
-  pub external fn floor(Float) -> Float =
+if javascript {
+  external fn do_ceiling(Float) -> Float =
+    "../gleam_stdlib.js" "ceiling"
+}
+
+/// Rounds the value to the next lowest whole number as a float.
+///
+/// ## Examples
+///
+///    > floor(2.3)
+///    2.0
+///
+pub fn floor(float: Float) -> Float {
+  do_floor(float)
+}
+
+if erlang {
+  external fn do_floor(Float) -> Float =
     "math" "floor"
+}
 
-  /// Rounds the value to the nearest whole number as an int.
-  ///
-  /// ## Examples
-  ///
-  ///    > round(2.3)
-  ///    2
-  ///
-  ///    > round(2.5)
-  ///    3
-  ///
-  pub external fn round(Float) -> Int =
-    "erlang" "round"
+if javascript {
+  external fn do_floor(Float) -> Float =
+    "../gleam_stdlib.js" "floor"
+}
+
+/// Rounds the value to the nearest whole number as an int.
+///
+/// ## Examples
+///
+///    > round(2.3)
+///    2
+///
+///    > round(2.5)
+///    3
+///
+pub fn round(float: Float) -> Int {
+  do_round(float)
+}
 
+if erlang {
+  external fn do_round(Float) -> Int =
+    "math" "round"
+}
+
+if javascript {
+  fn do_round(float: Float) -> Int {
+    case float >=. 0.0 {
+      True -> js_round(float)
+      _ -> 0 - js_round(negate(float))
+    }
+  }
+
+  external fn js_round(Float) -> Int =
+    "../gleam_stdlib.js" "round"
+}
+
+if erlang {
   /// Returns the value as an int, truncating all decimal digits.
   ///
   /// ## Examples
diff --git a/src/gleam_stdlib.js b/src/gleam_stdlib.js
index 95fb526..8b2f131 100644
--- a/src/gleam_stdlib.js
+++ b/src/gleam_stdlib.js
@@ -224,3 +224,15 @@ export function print(string) {
     console.log(string); // We're in a browser. Newlines are mandated
   }
 }
+
+export function ceiling(float) {
+  return Math.ceil(float);
+}
+
+export function floor(float) {
+  return Math.floor(float);
+}
+
+export function round(float) {
+  return Math.round(float);
+}
diff --git a/test/gleam/float_test.gleam b/test/gleam/float_test.gleam
index 9eff3a3..a449f79 100644
--- a/test/gleam/float_test.gleam
+++ b/test/gleam/float_test.gleam
@@ -1,9 +1,6 @@
 import gleam/should
 import gleam/float
-
-if erlang {
-  import gleam/order
-}
+import gleam/order
 
 pub fn parse_test() {
   "1.23"
@@ -49,92 +46,92 @@ pub fn to_string_test() {
   |> should.equal("-8.1")
 }
 
-if erlang {
-  pub fn clamp_test() {
-    float.clamp(1.4, min: 1.3, max: 1.5)
-    |> should.equal(1.4)
+pub fn clamp_test() {
+  float.clamp(1.4, min: 1.3, max: 1.5)
+  |> should.equal(1.4)
 
-    float.clamp(1.2, min: 1.3, max: 1.5)
-    |> should.equal(1.3)
+  float.clamp(1.2, min: 1.3, max: 1.5)
+  |> should.equal(1.3)
 
-    float.clamp(1.6, min: 1.3, max: 1.5)
-    |> should.equal(1.5)
-  }
+  float.clamp(1.6, min: 1.3, max: 1.5)
+  |> should.equal(1.5)
+}
 
-  pub fn compare_test() {
-    float.compare(0., 0.)
-    |> should.equal(order.Eq)
+pub fn compare_test() {
+  float.compare(0., 0.)
+  |> should.equal(order.Eq)
 
-    float.compare(0.1, 0.1)
-    |> should.equal(order.Eq)
+  float.compare(0.1, 0.1)
+  |> should.equal(order.Eq)
 
-    float.compare(0., 0.1)
-    |> should.equal(order.Lt)
+  float.compare(0., 0.1)
+  |> should.equal(order.Lt)
 
-    float.compare(-2., -1.9)
-    |> should.equal(order.Lt)
+  float.compare(-2., -1.9)
+  |> should.equal(order.Lt)
 
-    float.compare(2., 1.9)
-    |> should.equal(order.Gt)
+  float.compare(2., 1.9)
+  |> should.equal(order.Gt)
 
-    float.compare(-1.9, -2.)
-    |> should.equal(order.Gt)
-  }
+  float.compare(-1.9, -2.)
+  |> should.equal(order.Gt)
+}
 
-  pub fn ceiling_test() {
-    8.1
-    |> float.ceiling
-    |> should.equal(9.0)
+pub fn ceiling_test() {
+  8.1
+  |> float.ceiling
+  |> should.equal(9.0)
 
-    -8.1
-    |> float.ceiling
-    |> should.equal(-8.0)
+  -8.1
+  |> float.ceiling
+  |> should.equal(-8.0)
 
-    -8.0
-    |> float.ceiling
-    |> should.equal(-8.0)
-  }
+  -8.0
+  |> float.ceiling
+  |> should.equal(-8.0)
+}
 
-  pub fn floor_test() {
-    8.1
-    |> float.floor
-    |> should.equal(8.0)
+pub fn floor_test() {
+  8.1
+  |> float.floor
+  |> should.equal(8.0)
 
-    -8.1
-    |> float.floor
-    |> should.equal(-9.0)
+  -8.1
+  |> float.floor
+  |> should.equal(-9.0)
 
-    -8.0
-    |> float.floor
-    |> should.equal(-8.0)
-  }
+  -8.0
+  |> float.floor
+  |> should.equal(-8.0)
+}
 
-  pub fn round_test() {
-    8.1
-    |> float.round
-    |> should.equal(8)
+pub fn round_test() {
+  8.1
+  |> float.round
+  |> should.equal(8)
 
-    8.4
-    |> float.round
-    |> should.equal(8)
+  8.4
+  |> float.round
+  |> should.equal(8)
 
-    8.499
-    |> float.round
-    |> should.equal(8)
+  8.499
+  |> float.round
+  |> should.equal(8)
 
-    8.5
-    |> float.round
-    |> should.equal(9)
+  8.5
+  |> float.round
+  |> should.equal(9)
 
-    -8.1
-    |> float.round
-    |> should.equal(-8)
+  -8.1
+  |> float.round
+  |> should.equal(-8)
 
-    -7.5
-    |> float.round
-    |> should.equal(-8)
-  }
+  -7.5
+  |> float.round
+  |> should.equal(-8)
+}
 
+if erlang {
   pub fn truncate_test() {
     8.1
     |> float.truncate