Add acosh to Math

Author: jonathan-s

src/js.rs

@@ -250,6 +250,14 @@ extern {
     #[wasm_bindgen(static_method_of = Math)]
     pub fn acos(adjacent: i32, hypotenuse: i32) -> Number;
 
+    /// The Math.acosh() function returns the hyperbolic arc-cosine of a
+    /// number, that is ∀x ≥ 1
+    /// Math.acosh(x) = arcosh(x) = the unique y ≥ 0 such that cosh(y) = x
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/acosh
+    #[wasm_bindgen(static_method_of = Math)]
+    pub fn acosh(number: i32) -> Number;
+
 }
 
 // Number.

tests/all/js_globals/Math.rs

@@ -55,3 +55,30 @@ fn acos() {
         "#)
         .test()
 }
+
+#[test]
+fn acosh() {
+    project()
+        .file("src/lib.rs", r#"
+            #![feature(proc_macro, wasm_custom_section)]
+
+            extern crate wasm_bindgen;
+            use wasm_bindgen::prelude::*;
+            use wasm_bindgen::js;
+
+            #[wasm_bindgen]
+            pub fn acosh(number: i32) -> js::Number {
+                js::Math::acosh(number)
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                assert.equal(wasm.acosh(1), 0);
+                assert.equal(wasm.acosh(2), Math.acosh(2));
+            }
+        "#)
+        .test()
+}