Add denseProxy, various collection.js improvements

[Pisces] / value.test.js

diff --git a/value.test.js b/value.test.js
index babd59d9a449972170a6d3d6b673f557826d72d0..c55b591eb97c64ca9f5d6b83147067cc1a063829 100644 (file)
--- a/value.test.js
+++ b/value.test.js
@@ -1,13 +1,17 @@
-// ♓🌟 Piscēs ∷ value.test.js
-// ====================================================================
-//
-// Copyright © 2022–2023 Lady [@ Lady’s Computer].
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this
-// file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
+// SPDX-FileCopyrightText: 2022, 2023, 2025 Lady <https://www.ladys.computer/about/#lady>
+// SPDX-License-Identifier: MPL-2.0
+/**
+ * ⁌ ♓🌟 Piscēs ∷ value.test.js
+ *
+ * Copyright © 2022–2023, 2025 Lady [@ Ladys Computer].
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
+ */

 
 import {
 
 import {

+  assertEquals,

   assertStrictEquals,
   assertThrows,
   describe,
   assertStrictEquals,
   assertThrows,
   describe,


@@ -15,29 +19,54 @@ import {
 } from "./dev-deps.js";
 import {
   ASYNC_ITERATOR,
 } from "./dev-deps.js";
 import {
   ASYNC_ITERATOR,

-  canonicalNumericIndexString,
+  canonicalNumericIndexSting,
+  completePropertyDescriptor,

   HAS_INSTANCE,
   IS_CONCAT_SPREADABLE,
   HAS_INSTANCE,
   IS_CONCAT_SPREADABLE,

+  isAccessorDescriptor,
+  isArrayIndexString,
+  isDataDescriptor,
+  isFullyPopulatedDescriptor,
+  isGenericDescriptor,

   isIntegerIndexString,
   ITERATOR,
   isIntegerIndexString,
   ITERATOR,

-  lengthOfArraylike,
+  LN_10,
+  LN_2,
+  LOG10_𝑒,
+  LOG2_𝑒,

   MATCH,
   MATCH_ALL,
   MATCH,
   MATCH_ALL,

+  MAXIMUM_NUMBER,
+  MAXIMUM_SAFE_INTEGRAL_NUMBER,
+  MINIMUM_NUMBER,
+  MINIMUM_SAFE_INTEGRAL_NUMBER,
+  NAN,
+  NEGATIVE_INFINITY,
+  NEGATIVE_ZERO,

   NULL,
   ordinaryToPrimitive,
   NULL,
   ordinaryToPrimitive,

+  POSITIVE_INFINITY,
+  POSITIVE_ZERO,
+  RECIPROCAL_SQRT_2,

   REPLACE,
   sameValue,
   sameValueZero,
   SPECIES,
   SPLIT,
   REPLACE,
   sameValue,
   sameValueZero,
   SPECIES,
   SPLIT,

+  SQRT_2,

   TO_PRIMITIVE,
   TO_STRING_TAG,
   TO_PRIMITIVE,
   TO_STRING_TAG,

+  toFunctionName,

   toIndex,
   toLength,
   toPrimitive,
   toIndex,
   toLength,
   toPrimitive,

+  toPropertyKey,

   type,
   UNDEFINED,
   UNSCOPABLES,
   type,
   UNDEFINED,
   UNSCOPABLES,

+  𝑒,
+  𝜀,
+  𝜋,

 } from "./value.js";
 
 describe("ASYNC_ITERATOR", () => {
 } from "./value.js";
 
 describe("ASYNC_ITERATOR", () => {


@@ -67,6 +96,30 @@ describe("ITERATOR", () => {
   });
 });
 
   });
 });
 

+describe("LN_10", () => {
+  it("[[Get]] is ln(10)", () => {
+    assertStrictEquals(LN_10, Math.LN10);
+  });
+});
+
+describe("LN_2", () => {
+  it("[[Get]] is ln(2)", () => {
+    assertStrictEquals(LN_2, Math.LN2);
+  });
+});
+
+describe("LOG10_𝑒", () => {
+  it("[[Get]] is log10(𝑒)", () => {
+    assertStrictEquals(LOG10_𝑒, Math.LOG10E);
+  });
+});
+
+describe("LOG2_𝑒", () => {
+  it("[[Get]] is log2(ℇ)", () => {
+    assertStrictEquals(LOG2_𝑒, Math.LOG2E);
+  });
+});
+

 describe("MATCH", () => {
   it("[[Get]] is @@match", () => {
     assertStrictEquals(MATCH, Symbol.match);
 describe("MATCH", () => {
   it("[[Get]] is @@match", () => {
     assertStrictEquals(MATCH, Symbol.match);


@@ -79,12 +132,78 @@ describe("MATCH_ALL", () => {
   });
 });
 
   });
 });
 

+describe("MAXIMUM_NUMBER", () => {
+  it("[[Get]] is the maximum number", () => {
+    assertStrictEquals(MAXIMUM_NUMBER, Number.MAX_VALUE);
+  });
+});
+
+describe("MAXIMUM_SAFE_INTEGRAL_NUMBER", () => {
+  it("[[Get]] is the maximum safe integral number", () => {
+    assertStrictEquals(
+      MAXIMUM_SAFE_INTEGRAL_NUMBER,
+      Number.MAX_SAFE_INTEGER,
+    );
+  });
+});
+
+describe("MINIMUM_NUMBER", () => {
+  it("[[Get]] is the minimum number", () => {
+    assertStrictEquals(MINIMUM_NUMBER, Number.MIN_VALUE);
+  });
+});
+
+describe("MINIMUM_SAFE_INTEGRAL_NUMBER", () => {
+  it("[[Get]] is the minimum safe integral number", () => {
+    assertStrictEquals(
+      MINIMUM_SAFE_INTEGRAL_NUMBER,
+      Number.MIN_SAFE_INTEGER,
+    );
+  });
+});
+
+describe("NAN", () => {
+  it("[[Get]] is nan", () => {
+    assertStrictEquals(NAN, NaN);
+  });
+});
+
+describe("NEGATIVE_INFINITY", () => {
+  it("[[Get]] is negative infinity", () => {
+    assertStrictEquals(NEGATIVE_INFINITY, -Infinity);
+  });
+});
+
+describe("NEGATIVE_ZERO", () => {
+  it("[[Get]] is negative zero", () => {
+    assertStrictEquals(NEGATIVE_ZERO, -0);
+  });
+});
+

 describe("NULL", () => {
   it("[[Get]] is null", () => {
     assertStrictEquals(NULL, null);
   });
 });
 
 describe("NULL", () => {
   it("[[Get]] is null", () => {
     assertStrictEquals(NULL, null);
   });
 });
 

+describe("POSITIVE_INFINITY", () => {
+  it("[[Get]] is negative infinity", () => {
+    assertStrictEquals(POSITIVE_INFINITY, Infinity);
+  });
+});
+
+describe("POSITIVE_ZERO", () => {
+  it("[[Get]] is positive zero", () => {
+    assertStrictEquals(POSITIVE_ZERO, 0);
+  });
+});
+
+describe("RECIPROCAL_SQRT_2", () => {
+  it("[[Get]] is sqrt(½)", () => {
+    assertStrictEquals(RECIPROCAL_SQRT_2, Math.SQRT1_2);
+  });
+});
+

 describe("REPLACE", () => {
   it("[[Get]] is @@replace", () => {
     assertStrictEquals(REPLACE, Symbol.replace);
 describe("REPLACE", () => {
   it("[[Get]] is @@replace", () => {
     assertStrictEquals(REPLACE, Symbol.replace);


@@ -103,6 +222,12 @@ describe("SPLIT", () => {
   });
 });
 
   });
 });
 

+describe("SQRT_2", () => {
+  it("[[Get]] is sqrt(2)", () => {
+    assertStrictEquals(SQRT_2, Math.SQRT2);
+  });
+});
+

 describe("TO_PRIMITIVE", () => {
   it("[[Get]] is @@toPrimitive", () => {
     assertStrictEquals(TO_PRIMITIVE, Symbol.toPrimitive);
 describe("TO_PRIMITIVE", () => {
   it("[[Get]] is @@toPrimitive", () => {
     assertStrictEquals(TO_PRIMITIVE, Symbol.toPrimitive);


@@ -180,102 +305,383 @@ describe("canonicalNumericIndexString", () => {
   });
 });
 
   });
 });
 

-describe("isIntegerIndexString", () => {
-  it("[[Call]] returns false for nonstrings", () => {
-    assertStrictEquals(isIntegerIndexString(1), false);
+describe("completePropertyDescriptor", () => {
+  it("[[Call]] completes a generic descriptor", () => {
+    const desc = {};
+    completePropertyDescriptor(desc);
+    assertEquals(desc, {
+      configurable: false,
+      enumerable: false,
+      value: undefined,
+      writable: false,
+    });

   });
 
   });
 

-  it("[[Call]] returns false for noncanonical strings", () => {
-    assertStrictEquals(isIntegerIndexString(""), false);
-    assertStrictEquals(isIntegerIndexString("01"), false);
+  it("[[Call]] completes a data descriptor", () => {
+    const desc = { value: undefined };
+    completePropertyDescriptor(desc);
+    assertEquals(desc, {
+      configurable: false,
+      enumerable: false,
+      value: undefined,
+      writable: false,
+    });
+  });
+
+  it("[[Call]] completes an accessor descriptor", () => {
+    const desc = { get: undefined };
+    completePropertyDescriptor(desc);
+    assertEquals(desc, {
+      configurable: false,
+      enumerable: false,
+      get: undefined,
+      set: undefined,
+    });
+  });
+
+  it("[[Call]] throws an error when the descriptor is undefined", () => {
+    assertThrows(() => new completePropertyDescriptor(undefined));
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new completePropertyDescriptor({}));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(completePropertyDescriptor.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        completePropertyDescriptor.name,
+        "completePropertyDescriptor",
+      );
+    });
+  });
+});
+
+describe("isAccessorDescriptor", () => {
+  it("[[Call]] returns false for a generic descriptor", () => {
+    assertStrictEquals(isAccessorDescriptor({}), false);
+  });
+
+  it("[[Get]] returns false for a data descriptor", () => {

     assertStrictEquals(
     assertStrictEquals(

-      isIntegerIndexString("9007199254740993"),
+      isAccessorDescriptor({ value: undefined }),
+      false,
+    );
+    assertStrictEquals(
+      isAccessorDescriptor({ writable: undefined }),

       false,
     );
   });
 
       false,
     );
   });
 

+  it("[[Get]] returns true for an accessor descriptor", () => {
+    assertStrictEquals(isAccessorDescriptor({ get: undefined }), true);
+    assertStrictEquals(isAccessorDescriptor({ set: undefined }), true);
+  });
+
+  it("[[Get]] returns false for undefined", () => {
+    assertStrictEquals(isAccessorDescriptor(undefined), false);
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new isAccessorDescriptor({}));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(isAccessorDescriptor.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        isAccessorDescriptor.name,
+        "isAccessorDescriptor",
+      );
+    });
+  });
+});
+
+describe("isArrayIndexString", () => {
+  it("[[Call]] returns false for nonstrings", () => {
+    assertStrictEquals(isArrayIndexString(1), false);
+  });
+
+  it("[[Call]] returns false for noncanonical strings", () => {
+    assertStrictEquals(isArrayIndexString(""), false);
+    assertStrictEquals(isArrayIndexString("01"), false);
+    assertStrictEquals(isArrayIndexString("9007199254740993"), false);
+  });
+

   it("[[Call]] returns false for nonfinite numbers", () => {
   it("[[Call]] returns false for nonfinite numbers", () => {

-    assertStrictEquals(isIntegerIndexString("NaN"), false);
-    assertStrictEquals(isIntegerIndexString("Infinity"), false);
-    assertStrictEquals(isIntegerIndexString("-Infinity"), false);
+    assertStrictEquals(isArrayIndexString("NaN"), false);
+    assertStrictEquals(isArrayIndexString("Infinity"), false);
+    assertStrictEquals(isArrayIndexString("-Infinity"), false);

   });
 
   it("[[Call]] returns false for negative numbers", () => {
   });
 
   it("[[Call]] returns false for negative numbers", () => {

-    assertStrictEquals(isIntegerIndexString("-0"), false);
-    assertStrictEquals(isIntegerIndexString("-1"), false);
+    assertStrictEquals(isArrayIndexString("-0"), false);
+    assertStrictEquals(isArrayIndexString("-1"), false);

   });
 
   it("[[Call]] returns false for nonintegers", () => {
   });
 
   it("[[Call]] returns false for nonintegers", () => {

-    assertStrictEquals(isIntegerIndexString("0.25"), false);
-    assertStrictEquals(isIntegerIndexString("1.1"), false);
+    assertStrictEquals(isArrayIndexString("0.25"), false);
+    assertStrictEquals(isArrayIndexString("1.1"), false);

   });
 
   });
 

-  it("[[Call]] returns false for numbers greater than or equal to 2 ** 53", () => {
+  it("[[Call]] returns false for numbers greater than or equal to -1 >>> 0", () => {
+    assertStrictEquals(isArrayIndexString(String(-1 >>> 0)), false);

     assertStrictEquals(
     assertStrictEquals(

-      isIntegerIndexString("9007199254740992"),
+      isArrayIndexString(String((-1 >>> 0) + 1)),

       false,
     );
   });
 
       false,
     );
   });
 

-  it("[[Call]] returns true for safe canonical integer strings", () => {
-    assertStrictEquals(isIntegerIndexString("0"), true);
-    assertStrictEquals(isIntegerIndexString("9007199254740991"), true);
+  it("[[Call]] returns true for array lengths less than -1 >>> 0", () => {
+    assertStrictEquals(isArrayIndexString("0"), true);
+    assertStrictEquals(
+      isArrayIndexString(String((-1 >>> 0) - 1)),
+      true,
+    );
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new isArrayIndexString("0"));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(isArrayIndexString.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        isArrayIndexString.name,
+        "isArrayIndexString",
+      );
+    });

   });
 });
 
   });
 });
 

-describe("lengthOfArraylike", () => {
-  it("[[Call]] returns the length", () => {
+describe("isDataDescriptor", () => {
+  it("[[Call]] returns false for a generic descriptor", () => {
+    assertStrictEquals(isDataDescriptor({}), false);
+  });
+
+  it("[[Get]] returns true for a data descriptor", () => {
+    assertStrictEquals(isDataDescriptor({ value: undefined }), true);
+    assertStrictEquals(isDataDescriptor({ writable: true }), true);
+  });
+
+  it("[[Get]] returns false for an accessor descriptor", () => {
+    assertStrictEquals(isDataDescriptor({ get: undefined }), false);
+    assertStrictEquals(isDataDescriptor({ set: undefined }), false);
+  });
+
+  it("[[Get]] returns false for undefined", () => {
+    assertStrictEquals(isDataDescriptor(undefined), false);
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new isDataDescriptor({}));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(isDataDescriptor.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(isDataDescriptor.name, "isDataDescriptor");
+    });
+  });
+});
+
+describe("isFullyPopulatedDescriptor", () => {
+  it("[[Call]] returns false for a generic descriptor", () => {
+    assertStrictEquals(isFullyPopulatedDescriptor({}), false);
+  });
+
+  it("[[Get]] returns false for a non‐fully‐populated data descriptor", () => {
+    assertStrictEquals(
+      isFullyPopulatedDescriptor({ value: undefined }),
+      false,
+    );

     assertStrictEquals(
     assertStrictEquals(

-      lengthOfArraylike({ length: 9007199254740991 }),
-      9007199254740991,
+      isFullyPopulatedDescriptor({ writable: true }),
+      false,

     );
   });
 
     );
   });
 

-  it("[[Call]] returns a non·nan result", () => {
-    assertStrictEquals(lengthOfArraylike({ length: NaN }), 0);
-    assertStrictEquals(lengthOfArraylike({ length: "failure" }), 0);
+  it("[[Get]] returns true for a fully‐populated data descriptor", () => {
+    assertStrictEquals(
+      isFullyPopulatedDescriptor({
+        configurable: true,
+        enumerable: true,
+        value: undefined,
+        writable: true,
+      }),
+      true,
+    );

   });
 
   });
 

-  it("[[Call]] returns an integral result", () => {
-    assertStrictEquals(lengthOfArraylike({ length: 0.25 }), 0);
-    assertStrictEquals(lengthOfArraylike({ length: 1.1 }), 1);
+  it("[[Get]] returns false for a non‐fully‐populated accessor descriptor", () => {
+    assertStrictEquals(
+      isFullyPopulatedDescriptor({ get: undefined }),
+      false,
+    );
+    assertStrictEquals(
+      isFullyPopulatedDescriptor({ set: undefined }),
+      false,
+    );

   });
 
   });
 

-  it("[[Call]] returns a result greater than or equal to zero", () => {
-    assertStrictEquals(lengthOfArraylike({ length: -0 }), 0);
-    assertStrictEquals(lengthOfArraylike({ length: -1 }), 0);
-    assertStrictEquals(lengthOfArraylike({ length: -Infinity }), 0);
+  it("[[Get]] returns true for a fully‐populated accessor descriptor", () => {
+    assertStrictEquals(
+      isFullyPopulatedDescriptor({
+        configurable: true,
+        enumerable: true,
+        get: undefined,
+        set: undefined,
+      }),
+      true,
+    );

   });
 
   });
 

-  it("[[Call]] returns a result less than 2 ** 53", () => {
+  it("[[Get]] returns false for undefined", () => {
+    assertStrictEquals(isFullyPopulatedDescriptor(undefined), false);
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new isFullyPopulatedDescriptor({}));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(isFullyPopulatedDescriptor.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        isFullyPopulatedDescriptor.name,
+        "isFullyPopulatedDescriptor",
+      );
+    });
+  });
+});
+
+describe("isGenericDescriptor", () => {
+  it("[[Call]] returns true for a generic descriptor", () => {
+    assertStrictEquals(isGenericDescriptor({}), true);
+  });
+
+  it("[[Get]] returns false for a data descriptor", () => {
+    assertStrictEquals(
+      isGenericDescriptor({ value: undefined }),
+      false,
+    );
+    assertStrictEquals(isGenericDescriptor({ writable: true }), false);
+  });
+
+  it("[[Get]] returns false for an accessor descriptor", () => {
+    assertStrictEquals(isGenericDescriptor({ get: undefined }), false);
+    assertStrictEquals(isGenericDescriptor({ set: undefined }), false);
+  });
+
+  it("[[Get]] returns false for undefined", () => {
+    assertStrictEquals(isGenericDescriptor(undefined), false);
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new isGenericDescriptor({}));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(isGenericDescriptor.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        isGenericDescriptor.name,
+        "isGenericDescriptor",
+      );
+    });
+  });
+});
+
+describe("isIntegerIndexString", () => {
+  it("[[Call]] returns false for nonstrings", () => {
+    assertStrictEquals(isIntegerIndexString(1), false);
+  });
+
+  it("[[Call]] returns false for noncanonical strings", () => {
+    assertStrictEquals(isIntegerIndexString(""), false);
+    assertStrictEquals(isIntegerIndexString("01"), false);

     assertStrictEquals(
     assertStrictEquals(

-      lengthOfArraylike({ length: 9007199254740992 }),
-      9007199254740991,
+      isIntegerIndexString("9007199254740993"),
+      false,

     );
     );

+  });
+
+  it("[[Call]] returns false for nonfinite numbers", () => {
+    assertStrictEquals(isIntegerIndexString("NaN"), false);
+    assertStrictEquals(isIntegerIndexString("Infinity"), false);
+    assertStrictEquals(isIntegerIndexString("-Infinity"), false);
+  });
+
+  it("[[Call]] returns false for negative numbers", () => {
+    assertStrictEquals(isIntegerIndexString("-0"), false);
+    assertStrictEquals(isIntegerIndexString("-1"), false);
+  });
+
+  it("[[Call]] returns false for nonintegers", () => {
+    assertStrictEquals(isIntegerIndexString("0.25"), false);
+    assertStrictEquals(isIntegerIndexString("1.1"), false);
+  });
+
+  it("[[Call]] returns false for numbers greater than or equal to 2 ** 53", () => {

     assertStrictEquals(
     assertStrictEquals(

-      lengthOfArraylike({ length: Infinity }),
-      9007199254740991,
+      isIntegerIndexString("9007199254740992"),
+      false,

     );
   });
 
     );
   });
 

-  it("[[Call]] does not require an object argument", () => {
-    assertStrictEquals(lengthOfArraylike("string"), 6);
-    assertStrictEquals(lengthOfArraylike(Symbol()), 0);
+  it("[[Call]] returns true for safe canonical integer strings", () => {
+    assertStrictEquals(isIntegerIndexString("0"), true);
+    assertStrictEquals(isIntegerIndexString("9007199254740991"), true);

   });
 
   it("[[Construct]] throws an error", () => {
   });
 
   it("[[Construct]] throws an error", () => {

-    assertThrows(() => new lengthOfArraylike(""));
+    assertThrows(() => new isIntegerIndexString("0"));

   });
 
   describe(".length", () => {
     it("[[Get]] returns the correct length", () => {
   });
 
   describe(".length", () => {
     it("[[Get]] returns the correct length", () => {

-      assertStrictEquals(lengthOfArraylike.length, 1);
+      assertStrictEquals(isIntegerIndexString.length, 1);

     });
   });
 
   describe(".name", () => {
     it("[[Get]] returns the correct name", () => {
     });
   });
 
   describe(".name", () => {
     it("[[Get]] returns the correct name", () => {

-      assertStrictEquals(lengthOfArraylike.name, "lengthOfArraylike");
+      assertStrictEquals(
+        isIntegerIndexString.name,
+        "isIntegerIndexString",
+      );

     });
   });
 });
     });
   });
 });


@@ -493,6 +899,84 @@ describe("sameValueZero", () => {
   });
 });
 
   });
 });
 

+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", () => {
+    assertStrictEquals(
+      toFunctionName(Symbol("etaoin"), "foo"),
+      "foo [etaoin]",
+    );
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new toFunctionName(""));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(toFunctionName.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(
+        toFunctionName.name,
+        "toFunctionName",
+      );
+    });
+  });
+});
+

 describe("toIndex", () => {
   it("[[Call]] returns an index", () => {
     assertStrictEquals(toIndex(9007199254740991), 9007199254740991);
 describe("toIndex", () => {
   it("[[Call]] returns an index", () => {
     assertStrictEquals(toIndex(9007199254740991), 9007199254740991);


@@ -692,6 +1176,47 @@ describe("toPrimitive", () => {
   });
 });
 
   });
 });
 

+describe("toPropertyKey", () => {
+  it("returns a string or symbol", () => {
+    const sym = Symbol();
+    assertStrictEquals(toPropertyKey(sym), sym);
+    assertStrictEquals(
+      toPropertyKey(new String("success")),
+      "success",
+    );
+  });
+
+  it("favours the `toString` representation", () => {
+    assertStrictEquals(
+      toPropertyKey({
+        toString() {
+          return "success";
+        },
+        valueOf() {
+          return "failure";
+        },
+      }),
+      "success",
+    );
+  });
+
+  it("[[Construct]] throws an error", () => {
+    assertThrows(() => new toPropertyKey(""));
+  });
+
+  describe(".length", () => {
+    it("[[Get]] returns the correct length", () => {
+      assertStrictEquals(toPropertyKey.length, 1);
+    });
+  });
+
+  describe(".name", () => {
+    it("[[Get]] returns the correct name", () => {
+      assertStrictEquals(toPropertyKey.name, "toPropertyKey");
+    });
+  });
+});
+

 describe("type", () => {
   it('[[Call]] returns "null" for null', () => {
     assertStrictEquals(type(null), "null");
 describe("type", () => {
   it('[[Call]] returns "null" for null', () => {
     assertStrictEquals(type(null), "null");


@@ -729,3 +1254,21 @@ describe("type", () => {
     });
   });
 });
     });
   });
 });

+
+describe("𝑒", () => {
+  it("[[Get]] is 𝑒", () => {
+    assertStrictEquals(𝑒, Math.E);
+  });
+});
+
+describe("𝜀", () => {
+  it("[[Get]] is 𝜀", () => {
+    assertStrictEquals(𝜀, Number.EPSILON);
+  });
+});
+
+describe("𝜋", () => {
+  it("[[Get]] is 𝜋", () => {
+    assertStrictEquals(𝜋, Math.PI);
+  });
+});