String - lastIndexOf (#490)

Author: data-pup

src/js.rs

@@ -1889,6 +1889,14 @@ extern "C" {
     #[wasm_bindgen(method, js_class = "String", js_name = indexOf)]
     pub fn index_of(this: &JsString, search_value: &JsString, from_index: i32) -> i32;
 
+    /// The `lastIndexOf()` method returns the index within the calling String
+    /// object of the last occurrence of the specified value, searching
+    /// backwards from fromIndex.  Returns -1 if the value is not found.
+    ///
+    /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf
+    #[wasm_bindgen(method, js_class = "String", js_name = lastIndexOf)]
+    pub fn last_index_of(this: &JsString, search_value: &JsString, from_index: i32) -> i32;
+
     /// The `slice()` method extracts a section of a string and returns it as a
     /// new string, without modifying the original string.
     ///

tests/all/js_globals/JsString.rs

@@ -261,6 +261,45 @@ fn index_of() {
         .test()
 }
 
+#[test]
+fn last_index_of() {
+    project()
+        .file("src/lib.rs", r#"
+            #![feature(use_extern_macros, wasm_custom_section)]
+
+            extern crate wasm_bindgen;
+            use wasm_bindgen::prelude::*;
+            use wasm_bindgen::js;
+
+            #[wasm_bindgen]
+            pub fn string_last_index_of(this: &js::JsString, search_value: &js::JsString, from_index: i32) -> i32 {
+                this.last_index_of(search_value, from_index)
+            }
+        "#)
+        .file("test.js", r#"
+            import * as assert from "assert";
+            import * as wasm from "./out";
+
+            export function test() {
+                let str = "canal";
+                let len = str.length;
+
+                // TODO: remove second parameter once we have optional parameters
+                assert.equal(wasm.string_last_index_of(str, 'a', len), 3);
+                assert.equal(wasm.string_last_index_of(str, 'a', 2), 1);
+                assert.equal(wasm.string_last_index_of(str, 'a', 0), -1);
+                // TODO: remove second parameter once we have optional parameters
+                assert.equal(wasm.string_last_index_of(str, 'x', len), -1);
+                assert.equal(wasm.string_last_index_of(str, 'c', -5), 0);
+                assert.equal(wasm.string_last_index_of(str, 'c', 0), 0);
+                // TODO: remove second parameter once we have optional parameters
+                assert.equal(wasm.string_last_index_of(str, '', len), 5);
+                assert.equal(wasm.string_last_index_of(str, '', 2), 2);
+            }
+        "#)
+        .test()
+}
+
 #[test]
 fn slice() {
     project()