Optimized .to_property_key()

boa/src/builtins/property/mod.rs

@@ -449,6 +449,17 @@ impl From<i32> for PropertyKey {
     }
 }
 
+impl From<f64> for PropertyKey {
+    fn from(value: f64) -> Self {
+        use num_traits::cast::FromPrimitive;
+        if let Some(index) = u32::from_f64(value) {
+            return PropertyKey::Index(index);
+        }
+
+        PropertyKey::String(ryu_js::Buffer::new().format(value).into())
+    }
+}
+
 impl PartialEq<&str> for PropertyKey {
     fn eq(&self, other: &&str) -> bool {
         match self {

boa/src/exec/mod.rs

@@ -510,13 +510,21 @@ impl Interpreter {
     /// https://tc39.es/ecma262/#sec-topropertykey
     #[allow(clippy::wrong_self_convention)]
     pub(crate) fn to_property_key(&mut self, value: &Value) -> Result<PropertyKey, Value> {
-        let key = self.to_primitive(value, PreferredType::String)?;
-        if let Value::Symbol(ref symbol) = key {
-            Ok(PropertyKey::from(symbol.clone()))
-        } else {
-            let string = self.to_string(&key)?;
-            Ok(PropertyKey::from(string))
-        }
+        Ok(match *value {
+            // Fast path:
+            Value::Integer(integer) => integer.into(),
+            Value::Rational(rational) => rational.into(),
+            Value::String(ref string) => string.clone().into(),
+            Value::Symbol(ref symbol) => symbol.clone().into(),
+            // Slow path:
+            _ => match self.to_primitive(value, PreferredType::String)? {
+                Value::Integer(integer) => integer.into(),
+                Value::Rational(rational) => rational.into(),
+                Value::String(ref string) => string.clone().into(),
+                Value::Symbol(ref symbol) => symbol.clone().into(),
+                primitive => self.to_string(&primitive)?.into(),
+            },
+        })
     }
 
     /// https://tc39.es/ecma262/#sec-hasproperty