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Chris Tate
e1358fb563
In JavaScript sources, Math, JSON or Reflect read as a value lowered to an identity token, the string "[builtin Math]": typeof, String, `in`, descriptors and member calls through an alias all had string semantics. Each of these namespaces read as a value is now one object per program, built on first use, with Node 24's own properties in Node's order: function members are writable, configurable and non-enumerable with Node's `length`, the Math constants are read-only, and Symbol.toStringTag names the namespace. Members hold the same function values the spelled member read gives; a member without one throws its fence when called. Global reads, globalThis, destructuring and shorthand properties all produce the same object, and an object with a string Symbol.toStringTag coerces to "[object <tag>]". Direct member calls keep their static lowerings, so replacing or deleting a function member would not reach them: such changes throw SC1090. New properties and attribute-only redefinitions behave as in Node.
24 lines
1.2 KiB
JavaScript
24 lines
1.2 KiB
JavaScript
// Reflection over the namespace objects answers Node's property
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// attributes: members are own, non-enumerable properties, the Math
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// constants are read-only, and Symbol.toStringTag names the namespace.
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function show(object, key) {
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const d = Object.getOwnPropertyDescriptor(object, key);
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if (d === undefined) return `${String(key)}: none`;
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const value = typeof d.value === "function" ? `fn/${d.value.length}/${d.value.name}` : String(d.value);
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return `${String(key)}: ${value} ${d.writable} ${d.enumerable} ${d.configurable}`;
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}
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function inspect(object) {
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return [
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Object.hasOwn(object, "parse"),
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Object.hasOwn(object, "abs"),
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Object.keys(object).length,
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Object.getOwnPropertyNames(object).length,
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].join(" ");
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}
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console.log(show(Math, "abs"), "|", show(Math, "PI"), "|", show(Math, "max"));
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console.log(show(Math, Symbol.toStringTag), "|", show(JSON, "stringify"), "|", show(Reflect, "apply"));
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console.log(inspect(Math), "|", inspect(JSON), "|", inspect(Reflect));
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console.log(Object.getOwnPropertyNames(JSON).join(","));
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console.log(Object.getOwnPropertyNames(Math).slice(0, 5).join(","), Object.getOwnPropertyNames(Math).at(-1));
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console.log(Object.prototype.hasOwnProperty.call(Math, "random"), Object.keys(Reflect).length);
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