fix(math): correct Math.asinh for large finite inputs

core/engine/src/builtins/math/mod.rs

@@ -198,14 +198,21 @@ impl Math {
     /// [spec]: https://tc39.es/ecma262/#sec-math.asinh
     /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/asinh
     pub(crate) fn asinh(_: &JsValue, args: &[JsValue], context: &mut Context) -> JsResult<JsValue> {
-        Ok(args
-            .get_or_undefined(0)
-            // 1. Let n be ? ToNumber(x).
-            .to_number(context)?
-            // 2. If n is NaN, n is +0𝔽, n is -0𝔽, n is +∞𝔽, or n is -∞𝔽, return n.
-            // 3. Return an implementation-approximated value representing the result of the inverse hyperbolic sine of ℝ(n).
-            .asinh()
-            .into())
+        // 1/√f64::EPSILON, as established by the Boost math library.
+        const ASINH_LARGE_INPUT_THRESHOLD: f64 = 67_108_864.0;
+
+        // 1. Let n be ? ToNumber(x).
+        let n = args.get_or_undefined(0).to_number(context)?;
+        if n.is_finite() && n.abs() > ASINH_LARGE_INPUT_THRESHOLD {
+            let r = n.recip();
+            return Ok(
+                (n.signum() * (n.abs().ln() + std::f64::consts::LN_2 + 0.25 * r * r)).into(),
+            );
+        }
+
+        // 2. If n is NaN, n is +0𝔽, n is -0𝔽, n is +∞𝔽, or n is -∞𝔽, return n.
+        // 3. Return an implementation-approximated value representing the result of the inverse hyperbolic sine of ℝ(n).
+        Ok(n.asinh().into())
     }
 
     /// Get the arctangent of a number.

core/engine/src/builtins/math/tests.rs

@@ -42,6 +42,9 @@ fn asinh() {
     run_test_actions([
         TestAction::assert_eq("Math.asinh(1)", 0.881_373_587_019_543),
         TestAction::assert_eq("Math.asinh(0)", 0.0),
+        TestAction::assert_eq("Math.asinh(1e308)", 709.889_355_822_726_f64),
+        TestAction::assert_eq("Math.asinh(-1e308)", -709.889_355_822_726_f64),
+        TestAction::assert_eq("Math.asinh(Number.MAX_VALUE)", 710.475_860_073_943_9_f64),
     ]);
 }