LibJS: Prefer Value::to_string() over to_byte_string() in more places

We should always prefer working with String, and Value::to_string() may
even return a cached String if the Value refers to a primitive string,
but no caching occurs for ByteString.

Libraries/LibJS/Runtime/Array.cpp

@@ -243,10 +243,10 @@ ThrowCompletionOr<double> compare_array_elements(VM& vm, Value x, Value y, Funct
     }
 
     // 5. Let xString be ? ToString(x).
-    auto x_string = PrimitiveString::create(vm, TRY(x.to_byte_string(vm)));
+    auto x_string = PrimitiveString::create(vm, TRY(x.to_string(vm)));
 
     // 6. Let yString be ? ToString(y).
-    auto y_string = PrimitiveString::create(vm, TRY(y.to_byte_string(vm)));
+    auto y_string = PrimitiveString::create(vm, TRY(y.to_string(vm)));
 
     // 7. Let xSmaller be ! IsLessThan(xString, yString, true).
     auto x_smaller = MUST(is_less_than(vm, x_string, y_string, true));

Libraries/LibJS/Runtime/ArrayPrototype.cpp

@@ -838,9 +838,9 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayPrototype::join)
     };
 
     auto length = TRY(length_of_array_like(vm, this_object));
-    ByteString separator = ",";
+    String separator = ","_string;
     if (!vm.argument(0).is_undefined())
-        separator = TRY(vm.argument(0).to_byte_string(vm));
+        separator = TRY(vm.argument(0).to_string(vm));
     StringBuilder builder;
     for (size_t i = 0; i < length; ++i) {
         if (i > 0)
@@ -848,11 +848,11 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayPrototype::join)
         auto value = TRY(this_object->get(i));
         if (value.is_nullish())
             continue;
-        auto string = TRY(value.to_byte_string(vm));
+        auto string = TRY(value.to_string(vm));
         builder.append(string);
     }
 
-    return PrimitiveString::create(vm, builder.to_byte_string());
+    return PrimitiveString::create(vm, builder.to_string_without_validation());
 }
 
 // 23.1.3.19 Array.prototype.keys ( ), https://tc39.es/ecma262/#sec-array.prototype.keys
@@ -1650,7 +1650,7 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayPrototype::to_locale_string)
             auto locale_string_result = TRY(value.invoke(vm, vm.names.toLocaleString, locales, options));
 
             // ii. Set R to the string-concatenation of R and S.
-            auto string = TRY(locale_string_result.to_byte_string(vm));
+            auto string = TRY(locale_string_result.to_string(vm));
             builder.append(string);
         }
 
@@ -1658,7 +1658,7 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayPrototype::to_locale_string)
     }
 
     // 7. Return R.
-    return PrimitiveString::create(vm, builder.to_byte_string());
+    return PrimitiveString::create(vm, builder.to_string_without_validation());
 }
 
 // 23.1.3.33 Array.prototype.toReversed ( ), https://tc39.es/ecma262/#sec-array.prototype.toreversed

Libraries/LibJS/Runtime/StringConstructor.cpp

@@ -167,13 +167,11 @@ JS_DEFINE_NATIVE_FUNCTION(StringConstructor::raw)
     // 7. Let nextIndex be 0.
     // 8. Repeat,
     for (size_t i = 0; i < literal_count; ++i) {
-        auto next_key = ByteString::number(i);
-
         // a. Let nextLiteralVal be ? Get(literals, ! ToString(𝔽(nextIndex))).
-        auto next_literal_value = TRY(literals->get(next_key));
+        auto next_literal_value = TRY(literals->get(PropertyKey(i)));
 
         // b. Let nextLiteral be ? ToString(nextLiteralVal).
-        auto next_literal = TRY(next_literal_value.to_byte_string(vm));
+        auto next_literal = TRY(next_literal_value.to_string(vm));
 
         // c. Set R to the string-concatenation of R and nextLiteral.
         builder.append(next_literal);
@@ -188,7 +186,7 @@ JS_DEFINE_NATIVE_FUNCTION(StringConstructor::raw)
             auto next_substitution_value = vm.argument(i + 1);
 
             // ii. Let nextSub be ? ToString(nextSubVal).
-            auto next_substitution = TRY(next_substitution_value.to_byte_string(vm));
+            auto next_substitution = TRY(next_substitution_value.to_string(vm));
 
             // iii. Set R to the string-concatenation of R and nextSub.
             builder.append(next_substitution);

Libraries/LibJS/Runtime/TypedArrayPrototype.cpp

@@ -1987,7 +1987,7 @@ JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::to_locale_string)
         if (!next_element.is_nullish()) {
             // i. Let S be ? ToString(? Invoke(nextElement, "toLocaleString", « locales, options »)).
             auto locale_string_value = TRY(next_element.invoke(vm, vm.names.toLocaleString, locales, options));
-            auto locale_string = TRY(locale_string_value.to_byte_string(vm));
+            auto locale_string = TRY(locale_string_value.to_string(vm));
 
             // ii. Set R to the string-concatenation of R and S.
             builder.append(locale_string);
@@ -1997,7 +1997,7 @@ JS_DEFINE_NATIVE_FUNCTION(TypedArrayPrototype::to_locale_string)
     }
 
     // 7. Return R.
-    return PrimitiveString::create(vm, builder.to_byte_string());
+    return PrimitiveString::create(vm, builder.to_string_without_validation());
 }
 
 // 23.2.3.32 %TypedArray%.prototype.toReversed ( ), https://tc39.es/ecma262/#sec-%typedarray%.prototype.toreversed

Tests/LibJS/test-js.cpp

@@ -26,7 +26,7 @@ TESTJS_GLOBAL_FUNCTION(is_strict_mode, isStrictMode, 0)
 
 TESTJS_GLOBAL_FUNCTION(can_parse_source, canParseSource)
 {
-    auto source = TRY(vm.argument(0).to_byte_string(vm));
+    auto source = TRY(vm.argument(0).to_string(vm));
     auto parser = JS::Parser(JS::Lexer(source));
     (void)parser.parse_program();
     return JS::Value(!parser.has_errors());

Tests/LibWasm/test-wasm.cpp

@@ -21,7 +21,7 @@ TESTJS_GLOBAL_FUNCTION(read_binary_wasm_file, readBinaryWasmFile)
         return StringView { error_string, strlen(error_string) };
     };
 
-    auto filename = TRY(vm.argument(0).to_byte_string(vm));
+    auto filename = TRY(vm.argument(0).to_string(vm));
     auto file = Core::File::open(filename, Core::File::OpenMode::Read);
     if (file.is_error())
         return vm.throw_completion<JS::TypeError>(error_code_to_string(file.error().code()));