X-Git-Url: https://git.ladys.computer/Pisces/blobdiff_plain/37ab7f76d34b76493528f20e7427ef9534a8edf7..refs/heads/current:/function.test.js?ds=inline

diff --git a/function.test.js b/function.test.js
index 9be4db6..bf0e907 100644
--- a/function.test.js
+++ b/function.test.js
@@ -10,10 +10,14 @@
 import {
   assert,
   assertEquals,
+  assertNotStrictEquals,
+  assertSpyCall,
+  assertSpyCalls,
   assertStrictEquals,
   assertThrows,
   describe,
   it,
+  spy,
 } from "./dev-deps.js";
 import {
   bind,
@@ -23,11 +27,12 @@ import {
   createArrowFunction,
   createCallableFunction,
   createIllegalConstructor,
+  createProxyConstructor,
   identity,
   isCallable,
   isConstructor,
+  maybe,
   ordinaryHasInstance,
-  toFunctionName,
 } from "./function.js";
 
 describe("bind", () => {
@@ -465,9 +470,6 @@ describe("createIllegalConstructor", () => {
       Object.getPrototypeOf(constructor.prototype),
       Object.prototype,
     );
-    console.dir(
-      Object.getOwnPropertyDescriptors(constructor.prototype),
-    );
     assertEquals(
       constructor.prototype,
       Object.create(Object.prototype, {
@@ -489,6 +491,7 @@ describe("createIllegalConstructor", () => {
   it("[[Call]] returns a correctly‐formed constructor when provided one argument", () => {
     const constructorPrototype = Object.create(null, {
       name: { value: "etaoin" },
+      length: { value: "3" },
       prototype: { value: {} },
     });
     const constructor = createIllegalConstructor(
@@ -500,7 +503,7 @@ describe("createIllegalConstructor", () => {
       constructorPrototype,
     );
     assert(Object.hasOwn(constructor, "prototype"));
-    assertEquals(
+    assertStrictEquals(
       constructor.prototype,
       constructorPrototype.prototype,
     );
@@ -509,12 +512,59 @@ describe("createIllegalConstructor", () => {
         .writable,
     );
     assertStrictEquals(constructor.name, "etaoin");
+    assertStrictEquals(constructor.length, 3);
+  });
+
+  it("[[Call]] allows the length to be overridden", () => {
+    assertStrictEquals(
+      createIllegalConstructor(
+        function etaoin() {},
+        { length: 100 },
+      ).length,
+      100,
+    );
+  });
+
+  it("[[Call]] allows the name to be overridden", () => {
+    assertStrictEquals(
+      createIllegalConstructor(
+        function etaoin() {},
+        { name: "shrdlu" },
+      ).name,
+      "shrdlu",
+    );
+  });
+
+  it("[[Call]] allows the prototype to be overridden", () => {
+    const obj = {};
+    assertStrictEquals(
+      createIllegalConstructor(
+        function etaoin() {},
+        { prototype: obj },
+      ).prototype,
+      obj,
+    );
   });
 
   it("[[Construct]] throws an error", () => {
     assertThrows(() => new createIllegalConstructor(function () {}));
   });
 
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(createIllegalConstructor.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        createIllegalConstructor.name,
+        "createIllegalConstructor",
+      );
+    });
+  });
+
   describe("~", () => {
     it("[[Call]] throws an error", () => {
       assertThrows(() => {
@@ -528,18 +578,332 @@ describe("createIllegalConstructor", () => {
       });
     });
   });
+});
+
+describe("createProxyConstructor", () => {
+  it("[[Call]] returns a constructor", () => {
+    assert(isConstructor(createProxyConstructor({})));
+  });
+
+  it("[[Call]] throws with no arguments", () => {
+    assertThrows(() => createProxyConstructor());
+  });
+
+  it("[[Call]] throws if the second argument is not a constructor or undefined", () => {
+    assertThrows(() => createProxyConstructor({}, () => {}));
+  });
+
+  it("[[Call]] throws if the third argument is not a constructor or undefined", () => {
+    assertThrows(() =>
+      createProxyConstructor({}, undefined, () => {})
+    );
+  });
+
+  it("[[Call]] creates a proper proxy constructor", () => {
+    const constructorPrototype = function etaoin(_) {};
+    const constructor = class Constructor
+      extends constructorPrototype {
+      constructor(_1, _2, _3) {}
+    };
+    const proxyConstructor = createProxyConstructor(
+      {},
+      constructor,
+    );
+    assert(isConstructor(proxyConstructor));
+    assertStrictEquals(
+      Object.getPrototypeOf(proxyConstructor),
+      Proxy,
+    );
+    assertStrictEquals(proxyConstructor.prototype, undefined);
+    assertStrictEquals(proxyConstructor.name, "ConstructorProxy");
+    assertStrictEquals(proxyConstructor.length, 3);
+  });
+
+  it("[[Call]] allows the length to be overridden", () => {
+    assertStrictEquals(
+      createProxyConstructor({}, undefined, undefined, {
+        length: 100,
+      }).length,
+      100,
+    );
+  });
+
+  it("[[Call]] allows the name to be overridden", () => {
+    assertStrictEquals(
+      createProxyConstructor({}, function etaoin() {}, undefined, {
+        name: "shrdlu",
+      }).name,
+      "shrdlu",
+    );
+  });
+
+  it("[[Call]] does not allow the prototype to be overridden", () => {
+    assertStrictEquals(
+      createProxyConstructor({}, undefined, undefined, {
+        prototype: {},
+      }).prototype,
+      undefined,
+    );
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new createProxyConstructor({}));
+  });
 
   describe(".length", () => {
     it("[[Get]] returns the correct length", () => {
-      assertStrictEquals(createIllegalConstructor.length, 1);
+      assertStrictEquals(createProxyConstructor.length, 2);
     });
   });
 
   describe(".name", () => {
     it("[[Get]] returns the correct name", () => {
       assertStrictEquals(
-        createIllegalConstructor.name,
-        "createIllegalConstructor",
+        createProxyConstructor.name,
+        "createProxyConstructor",
+      );
+    });
+  });
+
+  describe("~", () => {
+    it("[[Call]] throws an error", () => {
+      assertThrows(() => {
+        createProxyConstructor({})();
+      });
+    });
+
+    it("[[Construct]] produces a proxy", () => {
+      const obj = {};
+      const proxyConstructor = createProxyConstructor({
+        get(O, P, Receiver) {
+          if (P === "etaoin") {
+            return Reflect.get(O, P, Receiver) ?? "success";
+          } else {
+            return Reflect.get(O, P, Receiver);
+          }
+        },
+      }, function () {
+        return obj;
+      });
+      const proxy = new proxyConstructor();
+      assertStrictEquals(proxy.etaoin, "success");
+      obj.etaoin = "shrdlu";
+      assertStrictEquals(proxy.etaoin, "shrdlu");
+    });
+
+    it("[[Construct]] receives the expected new.target", () => {
+      const constructor = function Constructor() {
+        return { name: new.target.name };
+      };
+      assertStrictEquals(
+        new (createProxyConstructor({}, constructor))().name,
+        "Constructor",
+      );
+      assertStrictEquals(
+        new (createProxyConstructor(
+          {},
+          constructor,
+          function NewTarget() {},
+        ))().name,
+        "NewTarget",
+      );
+    });
+  });
+
+  describe("~is[[.name]]", () => {
+    it("[[GetOwnProperty]] defines the appropriate method", () => {
+      assertNotStrictEquals(
+        Object.getOwnPropertyDescriptor(
+          createProxyConstructor({}),
+          "isProxy",
+        ),
+        undefined,
+      );
+      assertNotStrictEquals(
+        Object.getOwnPropertyDescriptor(
+          createProxyConstructor({}, function Base() {}),
+          "isBaseProxy",
+        ),
+        undefined,
+      );
+      assertNotStrictEquals(
+        Object.getOwnPropertyDescriptor(
+          createProxyConstructor({}, function Bad() {}, undefined, {
+            name: "⸺",
+          }),
+          "is⸺",
+        ),
+        undefined,
+      );
+    });
+
+    it("[[GetOwnProperty]] has the correct descriptor", () => {
+      const proxyConstructor = createProxyConstructor({});
+      assertEquals(
+        Object.getOwnPropertyDescriptor(
+          proxyConstructor,
+          "isProxy",
+        ),
+        {
+          configurable: true,
+          enumerable: false,
+          value: proxyConstructor.isProxy,
+          writable: true,
+        },
+      );
+    });
+
+    it("[[Call]] returns true for created proxies", () => {
+      const proxyConstructor = createProxyConstructor({});
+      const proxy = new proxyConstructor();
+      assertStrictEquals(
+        proxyConstructor.isProxy(proxy),
+        true,
+      );
+    });
+
+    it("[[Call]] returns false for nonproxies", () => {
+      const constructor = function Base() {};
+      const proxyConstructor = createProxyConstructor({}, constructor);
+      assertStrictEquals(
+        proxyConstructor.isBaseProxy(new constructor()),
+        false,
+      );
+    });
+
+    it("[[Construct]] throws an error", () => {
+      const proxyConstructor = createProxyConstructor({});
+      assertThrows(() => new proxyConstructor.isProxy({}));
+    });
+
+    describe(".length", () => {
+      it("[[Get]] returns the correct length", () => {
+        const proxyConstructor = createProxyConstructor({});
+        assertStrictEquals(proxyConstructor.isProxy.length, 1);
+      });
+    });
+
+    describe(".name", () => {
+      it("[[Get]] returns the correct name", () => {
+        const proxyConstructor = createProxyConstructor({});
+        assertStrictEquals(proxyConstructor.isProxy.name, "isProxy");
+        const otherProxyConstructor = createProxyConstructor(
+          {},
+          function Base() {},
+        );
+        assertStrictEquals(
+          otherProxyConstructor.isBaseProxy.name,
+          "isBaseProxy",
+        );
+      });
+    });
+  });
+
+  describe("~length", () => {
+    it("[[GetOwnProperty]] has the correct descriptor", () => {
+      assertEquals(
+        Object.getOwnPropertyDescriptor(
+          createProxyConstructor({}),
+          "length",
+        ),
+        {
+          configurable: true,
+          enumerable: false,
+          value: 1,
+          writable: false,
+        },
+      );
+    });
+  });
+
+  describe("~name", () => {
+    it("[[GetOwnProperty]] has the correct descriptor", () => {
+      assertEquals(
+        Object.getOwnPropertyDescriptor(
+          createProxyConstructor({}),
+          "name",
+        ),
+        {
+          configurable: true,
+          enumerable: false,
+          value: "Proxy",
+          writable: false,
+        },
+      );
+    });
+  });
+
+  describe("~prototype", () => {
+    it("[[GetOwnProperty]] has the correct descriptor", () => {
+      assertEquals(
+        Object.getOwnPropertyDescriptor(
+          createProxyConstructor({}),
+          "prototype",
+        ),
+        {
+          configurable: false,
+          enumerable: false,
+          value: undefined,
+          writable: false,
+        },
+      );
+    });
+  });
+
+  describe("~revocable", () => {
+    it("[[Call]] produces a revocable proxy", () => {
+      const obj = {};
+      const proxyConstructor = createProxyConstructor({
+        get(O, P, Receiver) {
+          if (P === "etaoin") {
+            return Reflect.get(O, P, Receiver) ?? "success";
+          } else {
+            return Reflect.get(O, P, Receiver);
+          }
+        },
+      }, function () {
+        return obj;
+      });
+      const { proxy, revoke } = proxyConstructor.revocable();
+      assertStrictEquals(proxy.etaoin, "success");
+      obj.etaoin = "shrdlu";
+      assertStrictEquals(proxy.etaoin, "shrdlu");
+      revoke();
+      assertThrows(() => proxy.etaoin);
+    });
+
+    it("[[Call]] receives the expected new.target", () => {
+      const constructor = function Constructor() {
+        return { name: new.target.name };
+      };
+      assertStrictEquals(
+        createProxyConstructor({}, constructor).revocable().proxy.name,
+        "Constructor",
+      );
+      assertStrictEquals(
+        createProxyConstructor(
+          {},
+          constructor,
+          function NewTarget() {},
+        ).revocable().proxy.name,
+        "NewTarget",
+      );
+    });
+
+    it("[[Construct]] throws an error", () => {
+      assertThrows(() => new (createProxyConstructor({})).revocable());
+    });
+
+    it("[[GetOwnProperty]] has the correct descriptor", () => {
+      const proxyConstructor = createProxyConstructor({});
+      assertEquals(
+        Object.getOwnPropertyDescriptor(proxyConstructor, "revocable"),
+        {
+          configurable: true,
+          enumerable: false,
+          value: proxyConstructor.revocable,
+          writable: true,
+        },
       );
     });
   });
@@ -718,115 +1082,73 @@ describe("isConstructor", () => {
   });
 });
 
-describe("ordinaryHasInstance", () => {
-  it("[[Call]] walks the prototype chain", () => {
-    const constructor = class {
-      [Symbol.hasInstance]() {
-        return false;
-      }
-    };
-    assertStrictEquals(
-      ordinaryHasInstance(
-        constructor,
-        new class extends constructor {}(),
-      ),
-      true,
-    );
+describe("maybe", () => {
+  it("[[Call]] calls if not nullish", () => {
+    const wrapper = spy(() => "success");
+    assertStrictEquals(maybe(0, wrapper), "success");
+    assertSpyCalls(wrapper, 1);
+    assertSpyCall(wrapper, 0, {
+      args: [0],
+      self: undefined,
+      returned: "success",
+    });
+  });
+
+  it("[[Call]] does not call if nullish", () => {
+    const wrapper = spy(() => "success");
+    assertStrictEquals(maybe(null, wrapper), null);
+    assertStrictEquals(maybe(undefined, wrapper), undefined);
+    assertSpyCalls(wrapper, 0);
   });
 
   it("[[Construct]] throws an error", () => {
-    assertThrows(() => new ordinaryHasInstance(function () {}, {}));
+    assertThrows(() => new maybe(true, ($) => $));
   });
 
   describe(".length", () => {
     it("[[Get]] returns the correct length", () => {
-      assertStrictEquals(ordinaryHasInstance.length, 2);
+      assertStrictEquals(maybe.length, 2);
     });
   });
 
   describe(".name", () => {
     it("[[Get]] returns the correct name", () => {
-      assertStrictEquals(
-        ordinaryHasInstance.name,
-        "ordinaryHasInstance",
-      );
+      assertStrictEquals(maybe.name, "maybe");
     });
   });
 });
 
-describe("toFunctionName", () => {
-  it("[[Call]] works with strings and no prefix", () => {
-    assertStrictEquals(toFunctionName("etaoin"), "etaoin");
-  });
-
-  it("[[Call]] works with objects and no prefix", () => {
-    assertStrictEquals(
-      toFunctionName({
-        toString() {
-          return "etaoin";
-        },
-      }),
-      "etaoin",
-    );
-  });
-
-  it("[[Call]] works with descriptionless symbols and no prefix", () => {
-    assertStrictEquals(toFunctionName(Symbol()), "");
-  });
-
-  it("[[Call]] works with empty description symbols and no prefix", () => {
-    assertStrictEquals(toFunctionName(Symbol("")), "[]");
-  });
-
-  it("[[Call]] works with described symbols and no prefix", () => {
-    assertStrictEquals(toFunctionName(Symbol("etaoin")), "[etaoin]");
-  });
-
-  it("[[Call]] works with strings and a prefix", () => {
-    assertStrictEquals(toFunctionName("etaoin", "foo"), "foo etaoin");
-  });
-
-  it("[[Call]] works with objects and no prefix", () => {
-    assertStrictEquals(
-      toFunctionName({
-        toString() {
-          return "etaoin";
-        },
-      }, "foo"),
-      "foo etaoin",
-    );
-  });
-
-  it("[[Call]] works with descriptionless symbols and no prefix", () => {
-    assertStrictEquals(toFunctionName(Symbol(), "foo"), "foo ");
-  });
-
-  it("[[Call]] works with empty description symbols and no prefix", () => {
-    assertStrictEquals(toFunctionName(Symbol(""), "foo"), "foo []");
-  });
-
-  it("[[Call]] works with described symbols and no prefix", () => {
+describe("ordinaryHasInstance", () => {
+  it("[[Call]] walks the prototype chain", () => {
+    const constructor = class {
+      [Symbol.hasInstance]() {
+        return false;
+      }
+    };
     assertStrictEquals(
-      toFunctionName(Symbol("etaoin"), "foo"),
-      "foo [etaoin]",
+      ordinaryHasInstance(
+        constructor,
+        new class extends constructor {}(),
+      ),
+      true,
     );
   });
 
   it("[[Construct]] throws an error", () => {
-    assertThrows(() => new toFunctionName(""));
+    assertThrows(() => new ordinaryHasInstance(function () {}, {}));
   });
 
   describe(".length", () => {
     it("[[Get]] returns the correct length", () => {
-      assertStrictEquals(toFunctionName.length, 1);
+      assertStrictEquals(ordinaryHasInstance.length, 2);
     });
   });
 
   describe(".name", () => {
     it("[[Get]] returns the correct name", () => {
       assertStrictEquals(
-        toFunctionName.name,
-        "toFunctionName",
+        ordinaryHasInstance.name,
+        "ordinaryHasInstance",
       );
     });
   });