diff --git a/Changes.md b/Changes.md
index 2026d0766..5f539a081 100644
--- a/Changes.md
+++ b/Changes.md
@@ -99,6 +99,8 @@ Unreleased
   ([#970](https://github.com/melange-re/melange/pull/970))
 - BREAKING(runtime): Improve `Js.Float` and change some of its functions to
   pipe-last ([#968](https://github.com/melange-re/melange/pull/968))
+- BREAKING(runtime): Remove unnecessary `unit` argument from `Js.Math.atan2`
+  ([#972](https://github.com/melange-re/melange/pull/972))
 
 2.2.0 2023-12-05
 ---------------
diff --git a/jscomp/runtime/js_mapper_runtime.mli b/jscomp/runtime/js_mapper_runtime.mli
index 31791e8e4..7ffde9c2c 100644
--- a/jscomp/runtime/js_mapper_runtime.mli
+++ b/jscomp/runtime/js_mapper_runtime.mli
@@ -1,5 +1,5 @@
 (* Copyright (C) 2017 Authors of ReScript
- * 
+ *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
@@ -17,7 +17,7 @@
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Lesser General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Lesser General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *)
@@ -25,10 +25,6 @@
 val raiseWhenNotFound : 'a -> 'a
 
 val fromInt : int -> int array -> int -> int option
-(**
-  [fromInt len array int]
-  return the mapped [enum]
-*)
+(** [fromInt len array int] return the mapped [enum] *)
 
-val fromIntAssert : int -> (* len *)
-                           int array -> int -> int
+val fromIntAssert : int -> (* len *) int array -> int -> int
diff --git a/jscomp/runtime/js_math.ml b/jscomp/runtime/js_math.ml
index 152f04cce..3d3820015 100644
--- a/jscomp/runtime/js_math.ml
+++ b/jscomp/runtime/js_math.ml
@@ -20,7 +20,8 @@
  *
  * You should have received a copy of the GNU Lesser General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *)
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *)
 
 open Melange_mini_stdlib
 
@@ -86,7 +87,7 @@ external atanh : float -> float = "atanh"
 [@@mel.scope "Math"]
 (** hyperbolic arctangent in radians, can return NaN, ES2015 *)
 
-external atan2 : y:float -> x:float -> unit -> float = "atan2"
+external atan2 : y:float -> x:float -> float = "atan2"
 [@@mel.scope "Math"]
 (** arctangent of the quotient of x and y, mostly... this one's a bit weird *)
 
@@ -110,7 +111,8 @@ external ceil_float : float -> float = "ceil"
 
 external clz32 : int -> int = "clz32"
 [@@mel.scope "Math"]
-(** number of leading zero bits of the argument's 32 bit int representation, ES2015 *)
+(** number of leading zero bits of the argument's 32 bit int representation,
+    ES2015 *)
 (* can convert string, float etc. to number *)
 
 external cos : float -> float = "cos"
@@ -219,7 +221,8 @@ let random_int min max =
 
 external unsafe_round : float -> int = "round"
 [@@mel.scope "Math"]
-(** rounds to nearest integer, returns a value not representable as [int] if NaN *)
+(** rounds to nearest integer, returns a value not representable as [int] if
+    NaN *)
 
 external round : float -> float = "round"
 [@@mel.scope "Math"]
@@ -254,8 +257,10 @@ external tanh : float -> float = "tanh"
 
 external unsafe_trunc : float -> int = "trunc"
 [@@mel.scope "Math"]
-(** truncate, ie. remove fractional digits, returns a value not representable as [int] if NaN, ES2015 *)
+(** truncate, ie. remove fractional digits, returns a value not representable
+    as [int] if NaN, ES2015 *)
 
 external trunc : float -> float = "trunc"
 [@@mel.scope "Math"]
-(** truncate, ie. remove fractional digits, returns a value not representable as [int] if NaN, ES2015 *)
+(** truncate, ie. remove fractional digits, returns a value not representable
+    as [int] if NaN, ES2015 *)
diff --git a/jscomp/test/js_math_test.ml b/jscomp/test/js_math_test.ml
index 647457b24..0b9279236 100644
--- a/jscomp/test/js_math_test.ml
+++ b/jscomp/test/js_math_test.ml
@@ -17,7 +17,7 @@ let suites = Mt.[
   "asinh", (fun _ -> ApproxThreshold(0.001, 0.390, asinh 0.4));
   "atan", (fun _ -> ApproxThreshold(0.001, 0.380, atan 0.4));
   "atanh", (fun _ -> ApproxThreshold(0.001, 0.423, atanh 0.4));
-  "atan2", (fun _ -> ApproxThreshold(0.001, 0.588, atan2 ~x:0.6 ~y:0.4 ()));
+  "atan2", (fun _ -> ApproxThreshold(0.001, 0.588, atan2 ~x:0.6 ~y:0.4));
   "cbrt", (fun _ -> Eq(2., cbrt 8.));
   "unsafe_ceil_int", (fun _ -> Eq (4, unsafe_ceil_int 3.2));
   "ceil_int", (fun _ -> Eq(4, ceil_int 3.2));