LibJS: Add %TypedArray%.prototype.findIndex

3 files changed, 124 insertions, 0 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp b/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp
index 123b79447b..5ee62d2ea2 100644
--- a/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.cpp
@@ -28,6 +28,7 @@ void TypedArrayPrototype::initialize(GlobalObject& object)
     define_native_function(vm.names.at, at, 1, attr);
     define_native_function(vm.names.every, every, 1, attr);
     define_native_function(vm.names.find, find, 1, attr);
+    define_native_function(vm.names.findIndex, find_index, 1, attr);
 }
 
 TypedArrayPrototype::~TypedArrayPrototype()
@@ -154,6 +155,20 @@ JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::find)
     return result;
 }
 
+// 23.2.3.11 %TypedArray%.prototype.findIndex ( predicate [ , thisArg ] ), https://tc39.es/ecma262/#sec-%typedarray%.prototype.findindex
+JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::find_index)
+{
+    auto result_index = -1;
+    for_each_item(vm, global_object, "findIndex", [&](auto index, auto, auto callback_result) {
+        if (callback_result.to_boolean()) {
+            result_index = index;
+            return IterationDecision::Break;
+        }
+        return IterationDecision::Continue;
+    });
+    return Value(result_index);
+}
+
 // 23.2.3.1 get %TypedArray%.prototype.buffer, https://tc39.es/ecma262/#sec-get-%typedarray%.prototype.buffer
 JS_DEFINE_NATIVE_GETTER(TypedArrayPrototype::buffer_getter)
 {
diff --git a/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.h b/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.h
index be4c44d8b8..3763841295 100644
--- a/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.h
+++ b/Userland/Libraries/LibJS/Runtime/TypedArrayPrototype.h
@@ -27,6 +27,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(at);
     JS_DECLARE_NATIVE_FUNCTION(every);
     JS_DECLARE_NATIVE_FUNCTION(find);
+    JS_DECLARE_NATIVE_FUNCTION(find_index);
 };
 
 }
diff --git a/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.prototype.findIndex.js b/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.prototype.findIndex.js
new file mode 100644
index 0000000000..fa6f8db626
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.prototype.findIndex.js
@@ -0,0 +1,108 @@
+const TYPED_ARRAYS = [
+    Uint8Array,
+    Uint16Array,
+    Uint32Array,
+    Int8Array,
+    Int16Array,
+    Int32Array,
+    Float32Array,
+    Float64Array,
+];
+
+const BIGINT_TYPED_ARRAYS = [BigUint64Array, BigInt64Array];
+
+test("length is 1", () => {
+    TYPED_ARRAYS.forEach(T => {
+        expect(T.prototype.findIndex).toHaveLength(1);
+    });
+
+    BIGINT_TYPED_ARRAYS.forEach(T => {
+        expect(T.prototype.findIndex).toHaveLength(1);
+    });
+});
+
+describe("errors", () => {
+    function errorTests(T) {
+        test(`requires at least one argument (${T.name})`, () => {
+            expect(() => {
+                new T().findIndex();
+            }).toThrowWithMessage(
+                TypeError,
+                "TypedArray.prototype.findIndex() requires at least one argument"
+            );
+        });
+
+        test(`callback must be a function (${T.name})`, () => {
+            expect(() => {
+                new T().findIndex(undefined);
+            }).toThrowWithMessage(TypeError, "undefined is not a function");
+        });
+    }
+
+    TYPED_ARRAYS.forEach(T => errorTests(T));
+    BIGINT_TYPED_ARRAYS.forEach(T => errorTests(T));
+});
+
+describe("normal behaviour", () => {
+    test("basic functionality", () => {
+        TYPED_ARRAYS.forEach(T => {
+            const typedArray = new T([1, 2, 3]);
+
+            expect(typedArray.findIndex(value => value === 1)).toBe(0);
+            expect(typedArray.findIndex(value => value === 2)).toBe(1);
+            expect(typedArray.findIndex(value => value === 3)).toBe(2);
+            expect(typedArray.findIndex((value, index) => index === 1)).toBe(1);
+            expect(typedArray.findIndex(value => value == "1")).toBe(0);
+            expect(typedArray.findIndex(value => value === 10)).toBe(-1);
+        });
+
+        BIGINT_TYPED_ARRAYS.forEach(T => {
+            const typedArray = new T([1n, 2n, 3n]);
+
+            expect(typedArray.findIndex(value => value === 1n)).toBe(0);
+            expect(typedArray.findIndex(value => value === 2n)).toBe(1);
+            expect(typedArray.findIndex(value => value === 3n)).toBe(2);
+            expect(typedArray.findIndex((value, index) => index === 1)).toBe(1);
+            expect(typedArray.findIndex(value => value == 1)).toBe(0);
+            expect(typedArray.findIndex(value => value == "1")).toBe(0);
+            expect(typedArray.findIndex(value => value === 1)).toBe(-1);
+        });
+    });
+
+    test("never calls callback with empty array", () => {
+        function emptyTest(T) {
+            var callbackCalled = 0;
+            expect(
+                new T().findIndex(() => {
+                    callbackCalled++;
+                })
+            ).toBe(-1);
+            expect(callbackCalled).toBe(0);
+        }
+
+        TYPED_ARRAYS.forEach(T => emptyTest(T));
+        BIGINT_TYPED_ARRAYS.forEach(T => emptyTest(T));
+    });
+
+    test("calls callback once for every item", () => {
+        TYPED_ARRAYS.forEach(T => {
+            var callbackCalled = 0;
+            expect(
+                new T([1, 2, 3]).findIndex(() => {
+                    callbackCalled++;
+                })
+            ).toBe(-1);
+            expect(callbackCalled).toBe(3);
+        });
+
+        BIGINT_TYPED_ARRAYS.forEach(T => {
+            var callbackCalled = 0;
+            expect(
+                new T([1n, 2n, 3n]).findIndex(() => {
+                    callbackCalled++;
+                })
+            ).toBe(-1);
+            expect(callbackCalled).toBe(3);
+        });
+    });
+});