LibJS: Add symbol objects

This commit adds the following classes: SymbolObject, SymbolConstructor, SymbolPrototype, and Symbol. This commit does not introduce any new functionality to the Object class, so they cannot be used as property keys in objects.
2025-07-25 23:47:45 +00:00 · 2020-04-29 23:25:21 -07:00 · 2020-04-29 23:25:21 -07:00 · 4ced126704
commit 4ced126704
parent b5b08fba92
21 changed files with 819 additions and 3 deletions
--- a/Libraries/LibJS/Runtime/SymbolConstructor.cpp
+++ b/Libraries/LibJS/Runtime/SymbolConstructor.cpp
@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2020, Matthew Olsson <matthewcolsson@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibJS/Interpreter.h>
+#include <LibJS/Runtime/Error.h>
+#include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/SymbolConstructor.h>
+#include <LibJS/Runtime/SymbolObject.h>
+
+namespace JS {
+
+SymbolConstructor::SymbolConstructor()
+    : NativeFunction("Symbol", *interpreter().global_object().function_prototype())
+{
+    put("prototype", interpreter().global_object().symbol_prototype(), 0);
+    put("length", Value(0), Attribute::Configurable);
+
+    put_native_function("for", for_, 1, Attribute::Writable | Attribute::Configurable);
+    put_native_function("keyFor", key_for, 1, Attribute::Writable | Attribute::Configurable);
+
+    SymbolObject::initialize_well_known_symbols(interpreter());
+
+    put("iterator", SymbolObject::well_known_iterator(), 0);
+    put("asyncIterator", SymbolObject::well_known_async_terator(), 0);
+    put("match", SymbolObject::well_known_match(), 0);
+    put("matchAll", SymbolObject::well_known_match_all(), 0);
+    put("replace", SymbolObject::well_known_replace(), 0);
+    put("search", SymbolObject::well_known_search(), 0);
+    put("split", SymbolObject::well_known_split(), 0);
+    put("hasInstance", SymbolObject::well_known_has_instance(), 0);
+    put("isConcatSpreadable", SymbolObject::well_known_is_concat_spreadable(), 0);
+    put("unscopables", SymbolObject::well_known_unscopables(), 0);
+    put("species", SymbolObject::well_known_species(), 0);
+    put("toPrimitive", SymbolObject::well_known_to_primtive(), 0);
+    put("toStringTag", SymbolObject::well_known_to_string_tag(), 0);
+}
+
+SymbolConstructor::~SymbolConstructor()
+{
+}
+
+Value SymbolConstructor::call(Interpreter& interpreter)
+{
+    if (!interpreter.argument_count())
+        return js_symbol(interpreter, "", false);
+    return js_symbol(interpreter, interpreter.argument(0).to_string(interpreter), false);
+}
+
+Value SymbolConstructor::construct(Interpreter& interpreter)
+{
+    interpreter.throw_exception<TypeError>("Symbol is not a constructor");
+    return {};
+}
+
+Value SymbolConstructor::for_(Interpreter& interpreter)
+{
+    String description;
+    if (!interpreter.argument_count()) {
+        description = "undefined";
+    } else {
+        description = interpreter.argument(0).to_string(interpreter);
+    }
+
+    return SymbolObject::get_global(interpreter, description);
+}
+
+Value SymbolConstructor::key_for(Interpreter& interpreter)
+{
+    auto argument = interpreter.argument(0);
+    if (!argument.is_symbol()) {
+        interpreter.throw_exception<TypeError>(String::format("%s is not a symbol", argument.to_string_without_side_effects().characters()));
+        return {};
+    }
+
+    auto& symbol = argument.as_symbol();
+    if (symbol.is_global())
+        return js_string(interpreter, symbol.description());
+
+    return js_undefined();
+}
+
+}