Add to_fixed and to_exponential function

src/js.rs

@@ -246,6 +246,20 @@ extern {
     #[wasm_bindgen(catch, method, js_name = toPrecision)]
     pub fn to_precision(this: &Number, precision: u8) -> Result<String, JsValue>;
 
+    /// The toFixed() method returns a string representing the Number
+    /// object using fixed-point notation.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed
+    #[wasm_bindgen(catch, method, js_name = toFixed)]
+    pub fn to_fixed(this: &Number, digits: u8) -> Result<String, JsValue>;
+
+    /// The toExponential() method returns a string representing the Number
+    /// object in exponential notation.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed
+    #[wasm_bindgen(catch, method, js_name = toExponential)]
+    pub fn to_exponential(this: &Number, fraction_digits: u8) -> Result<String, JsValue>;
+
     /// The toString() method returns a string representing the
     /// specified Number object.
     ///

tests/all/js_globals/Number.rs

@@ -125,3 +125,67 @@ fn value_of() {
         "#)
         .test()
 }
+
+#[test]
+fn to_fixed() {
+    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 to_fixed(this: &js::Number, digits: u8) -> String {
+                let result = this.to_fixed(digits);
+                let result = match result {
+                    Ok(num) => num,
+                    Err(_err) => "RangeError".to_string()
+                };
+                result
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                assert.equal(wasm.to_fixed(123.456, 2), "123.46");
+                assert.equal(wasm.to_fixed(10, 101), "RangeError");
+            }
+        "#)
+        .test()
+}
+
+#[test]
+fn to_exponential() {
+    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 to_exponential(this: &js::Number, fraction_digits: u8) -> String {
+                let result = this.to_exponential(fraction_digits);
+                let result = match result {
+                    Ok(num) => num,
+                    Err(_err) => "RangeError".to_string()
+                };
+                result
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                assert.equal(wasm.to_exponential(123456, 2), "1.23e+5");
+                assert.equal(wasm.to_exponential(10, 101), "RangeError");
+            }
+        "#)
+        .test()
+}