fix(napi): convert u64 to u32 in serialization (#1478)

https://github.com/napi-rs/napi-rs/issues/1470
serde_json::Value parses positive integers to u64 types by default. When converting serde_json::Value to a js value, those numbers are converted to BigInts, even if they are within the bounds of the number primitive. The added checks converts an u64 to an u32 if possible to prevent this behavior.

Co-authored-by: m1212e <->

crates/napi/src/js_values/ser.rs

@@ -95,11 +95,19 @@ impl<'env> Serializer for Ser<'env> {
 
   #[cfg(feature = "napi6")]
   fn serialize_u64(self, v: u64) -> Result<Self::Ok> {
+    // https://github.com/napi-rs/napi-rs/issues/1470
+    // serde_json::Value by default uses u64 for positive integers. This results in napirs using a BigInt instead of a number when converting to a js value.
+    // To avoid this, we need to check if the value fits into a smaller number type.
+    // If this is the case, we use the smaller type instead.
+    if v <= u32::MAX.into() {
+      self.serialize_u32(v as u32)
+    } else {
       self
         .0
         .create_bigint_from_u64(v)
         .map(|js_number| js_number.raw)
     }
+  }
 
   #[cfg(all(
     any(