From bf1b2d63c6492bcf46d6643ce416c92c7e7a207b Mon Sep 17 00:00:00 2001 From: davidot Date: Mon, 28 Nov 2022 12:08:57 +0100 Subject: [PATCH] LibJS: Add spec comments and check for edge cases in Math.tanh --- Userland/Libraries/LibJS/Runtime/MathObject.cpp | 13 +++++++++++-- .../LibJS/Tests/builtins/Math/Math.tanh.js | 2 ++ 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/Userland/Libraries/LibJS/Runtime/MathObject.cpp b/Userland/Libraries/LibJS/Runtime/MathObject.cpp index 6fd42dc545..29bd30f326 100644 --- a/Userland/Libraries/LibJS/Runtime/MathObject.cpp +++ b/Userland/Libraries/LibJS/Runtime/MathObject.cpp @@ -636,13 +636,22 @@ JS_DEFINE_NATIVE_FUNCTION(MathObject::cosh) // 21.3.2.34 Math.tanh ( x ), https://tc39.es/ecma262/#sec-math.tanh JS_DEFINE_NATIVE_FUNCTION(MathObject::tanh) { + // 1. Let n be ? ToNumber(x). auto number = TRY(vm.argument(0).to_number(vm)); - if (number.is_nan()) - return js_nan(); + + // 2. If n is NaN, n is +0𝔽, or n is -0𝔽, return n. + if (number.is_nan() || number.is_positive_zero() || number.is_negative_zero()) + return number; + + // 3. If n is +∞𝔽, return 1𝔽. if (number.is_positive_infinity()) return Value(1); + + // 4. If n is -∞𝔽, return -1𝔽. if (number.is_negative_infinity()) return Value(-1); + + // 5. Return an implementation-approximated Number value representing the result of the hyperbolic tangent of ℝ(n). return Value(::tanh(number.as_double())); } diff --git a/Userland/Libraries/LibJS/Tests/builtins/Math/Math.tanh.js b/Userland/Libraries/LibJS/Tests/builtins/Math/Math.tanh.js index e24dae76c4..f34bbf6653 100644 --- a/Userland/Libraries/LibJS/Tests/builtins/Math/Math.tanh.js +++ b/Userland/Libraries/LibJS/Tests/builtins/Math/Math.tanh.js @@ -5,4 +5,6 @@ test("basic functionality", () => { expect(Math.tanh(Infinity)).toBe(1); expect(Math.tanh(-Infinity)).toBe(-1); expect(Math.tanh(1)).toBeCloseTo(0.7615941559557649); + expect(Math.tanh(NaN)).toBe(NaN); + expect(Math.tanh(-0.0)).toBe(-0.0); });