diff --git a/polars/lazy/functions.ts b/polars/lazy/functions.ts
index 2cd8692d..f8b63dec 100644
--- a/polars/lazy/functions.ts
+++ b/polars/lazy/functions.ts
@@ -150,7 +150,7 @@ export function intRange<T>(opts: {
   low: any;
   high: any;
   step: number;
-  eager: boolean;
+  eager?: boolean;
 });
 export function intRange(
   low: any,
@@ -177,8 +177,7 @@ export function intRange(opts: any, high?, step = 1, eager?): Series | Expr {
         .select(intRange(low, high, step).alias("intRange") as any)
         .getColumn("intRange") as any;
     }
-
-    return _Expr(pli.intRange(low, high, step));
+    return _Expr(pli.intRange(low, high, step, eager));
   }
 }
 /**  Alias for `pl.col("*")` */
diff --git a/src/conversion.rs b/src/conversion.rs
index 37d6f9e4..db61c9d5 100644
--- a/src/conversion.rs
+++ b/src/conversion.rs
@@ -624,11 +624,8 @@ impl FromNapiValue for Wrap<DataType> {
                 };
 
                 Ok(Wrap(dtype))
-                // Ok(Wrap(Schema::from(fields)))
-            }
-            _ => {
-                todo!()
             }
+            _ => Err(Error::new(Status::InvalidArg, "not a valid conversion to 'DataType'".to_owned()))
         }
     }
 }
diff --git a/src/lazy/dsl.rs b/src/lazy/dsl.rs
index 8c4b8fe8..addb260d 100644
--- a/src/lazy/dsl.rs
+++ b/src/lazy/dsl.rs
@@ -1525,13 +1525,13 @@ pub fn dtype_cols(dtypes: Vec<Wrap<DataType>>) -> crate::lazy::dsl::JsExpr {
 
 #[cfg(feature = "range")]
 #[napi(catch_unwind)]
-pub fn int_range(start: Wrap<Expr>, end: Wrap<Expr>, step: i64, dtype: Wrap<DataType>) -> JsExpr {
-    let dtype = dtype.0;
+pub fn int_range(start: Wrap<Expr>, end: Wrap<Expr>, step: i64, dtype: Option<Wrap<DataType>>) -> JsExpr {
+    let dtype = dtype.map(|d| d.0 as DataType);
 
     let mut result = dsl::int_range(start.0, end.0, step);
 
-    if dtype != DataType::Int64 {
-        result = result.cast(dtype)
+    if dtype.is_some() && dtype.clone().unwrap() != DataType::Int64 {
+        result = result.cast(dtype.clone().unwrap());
     }
 
     result.into()
@@ -1539,13 +1539,13 @@ pub fn int_range(start: Wrap<Expr>, end: Wrap<Expr>, step: i64, dtype: Wrap<Data
 
 #[cfg(feature = "range")]
 #[napi(catch_unwind)]
-pub fn int_ranges(start: Wrap<Expr>, end: Wrap<Expr>, step: i64, dtype: Wrap<DataType>) -> JsExpr {
-    let dtype = dtype.0;
+pub fn int_ranges(start: Wrap<Expr>, end: Wrap<Expr>, step: i64, dtype: Option<Wrap<DataType>>) -> JsExpr {
+    let dtype = dtype.map(|d| d.0 as DataType);
 
     let mut result = dsl::int_ranges(start.0, end.0, step);
 
-    if dtype != DataType::Int64 {
-        result = result.cast(DataType::List(Box::new(dtype)))
+    if dtype.is_some() && dtype.clone().unwrap() != DataType::Int64 {
+        result = result.cast(DataType::List(Box::new(dtype.clone().unwrap())));
     }
 
     result.into()