LibJS: Add ArrayBuffer

Libraries/LibJS/Tests/builtins/ArrayBuffer/ArrayBuffer.isView.js

@@ -0,0 +1,18 @@
+// Update when more typed arrays get added
+const TYPED_ARRAYS = [Uint8Array, Uint16Array, Uint32Array, Int8Array, Int16Array, Int32Array];
+
+test("basic functionality", () => {
+    expect(ArrayBuffer.isView).toHaveLength(1);
+
+    expect(ArrayBuffer.isView()).toBeFalse();
+    expect(ArrayBuffer.isView(null)).toBeFalse();
+    expect(ArrayBuffer.isView(undefined)).toBeFalse();
+    expect(ArrayBuffer.isView([])).toBeFalse();
+    expect(ArrayBuffer.isView({})).toBeFalse();
+    expect(ArrayBuffer.isView(123)).toBeFalse();
+    expect(ArrayBuffer.isView("foo")).toBeFalse();
+    expect(ArrayBuffer.isView(new ArrayBuffer())).toBeFalse();
+    TYPED_ARRAYS.forEach(T => {
+        expect(ArrayBuffer.isView(new T())).toBeTrue();
+    });
+});

Libraries/LibJS/Tests/builtins/ArrayBuffer/ArrayBuffer.js

@@ -0,0 +1,13 @@
+test("basic functionality", () => {
+    expect(ArrayBuffer).toHaveLength(1);
+    expect(ArrayBuffer.name).toBe("ArrayBuffer");
+    expect(ArrayBuffer.prototype.constructor).toBe(ArrayBuffer);
+    expect(new ArrayBuffer()).toBeInstanceOf(ArrayBuffer);
+    expect(typeof new ArrayBuffer()).toBe("object");
+});
+
+test("ArrayBuffer constructor must be invoked with 'new'", () => {
+    expect(() => {
+        ArrayBuffer();
+    }).toThrowWithMessage(TypeError, "ArrayBuffer constructor must be called with 'new'");
+});

Libraries/LibJS/Tests/builtins/ArrayBuffer/ArrayBuffer.prototype.byteLength.js

@@ -0,0 +1,6 @@
+test("basic functionality", () => {
+    expect(new ArrayBuffer().byteLength).toBe(0);
+    expect(new ArrayBuffer(1).byteLength).toBe(1);
+    expect(new ArrayBuffer(64).byteLength).toBe(64);
+    expect(new ArrayBuffer(123).byteLength).toBe(123);
+});