Merge pull request #323 from rail44/string-char_code_at

Support String.prototype.charCodeAt

src/js.rs

@@ -474,6 +474,16 @@ extern {
     #[wasm_bindgen(method, js_class = "String", js_name = charAt)]
     pub fn char_at(this: &JsString, index: u32) -> JsString;
 
+    /// The charCodeAt() method returns an integer between 0 and 65535 representing the UTF-16 code unit at
+    /// the given index (the UTF-16 code unit matches the Unicode code point for code points representable in
+    /// a single UTF-16 code unit, but might also be the first code unit of a surrogate pair for
+    /// code points not representable in a single UTF-16 code unit, e.g. Unicode code points > 0x10000).
+    /// If you want the entire code point value, use codePointAt().
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/charCodeAt
+    #[wasm_bindgen(method, js_class = "String", js_name = charCodeAt)]
+    pub fn char_code_at(this: &JsString, index: u32) -> Number;
+
     /// The indexOf() method returns the index within the calling String object of
     /// the first occurrence of the specified value, starting the search at fromIndex.
     /// Returns -1 if the value is not found.

tests/all/js_globals/JsString.rs

@@ -31,6 +31,35 @@ fn char_at() {
         .test()
 }
 
+#[test]
+fn char_code_at() {
+    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 string_char_code_at(this: &js::JsString, index: u32) -> js::Number {
+                this.char_code_at(index)
+            }
+        "#)
+        .file("test.ts", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            var anyString = 'Brave new world';
+
+            export function test() {
+                assert.equal(wasm.string_char_code_at(anyString, 0), 66);
+                assert.ok(isNaN(wasm.string_char_code_at(anyString, 999)));
+            }
+        "#)
+        .test()
+}
+
 #[test]
 fn starts_with() {
     project()