diff --git a/src/hdf5_hl.d.ts b/src/hdf5_hl.d.ts
index 07b8ae6..109b793 100644
--- a/src/hdf5_hl.d.ts
+++ b/src/hdf5_hl.d.ts
@@ -66,13 +66,13 @@ export declare class Attribute {
     name: string;
     metadata: Metadata;
     dtype: Dtype;
-    shape: number[];
+    shape: number[] | null;
     private _value?;
     private _json_value?;
     constructor(file_id: bigint, path: string, name: string);
-    get value(): OutputData;
-    get json_value(): JSONCompatibleOutputData;
-    to_array(): string | number | boolean | JSONCompatibleOutputData[];
+    get value(): OutputData | null;
+    get json_value(): JSONCompatibleOutputData | null;
+    to_array(): JSONCompatibleOutputData | null;
 }
 declare abstract class HasAttrs {
     file_id: bigint;
@@ -132,14 +132,14 @@ export declare class Dataset extends HasAttrs {
     refresh(): void;
     get metadata(): Metadata;
     get dtype(): Dtype;
-    get shape(): number[];
+    get shape(): number[] | null;
     get filters(): Filter[];
-    get value(): OutputData;
-    get json_value(): JSONCompatibleOutputData;
-    slice(ranges: Slice[]): OutputData;
+    get value(): OutputData | null;
+    get json_value(): JSONCompatibleOutputData | null;
+    slice(ranges: Slice[]): OutputData | null;
     write_slice(ranges: Slice[], data: any): void;
     create_region_reference(ranges: Slice[]): RegionReference;
-    to_array(): string | number | boolean | JSONCompatibleOutputData[];
+    to_array(): JSONCompatibleOutputData | null;
     resize(new_shape: number[]): number;
     make_scale(scale_name?: string): void;
     attach_scale(index: number, scale_dset_path: string): void;
@@ -148,7 +148,9 @@ export declare class Dataset extends HasAttrs {
     get_scale_name(): string | null;
     set_dimension_label(index: number, label: string): void;
     get_dimension_labels(): (string | null)[];
-    _value_getter(json_compatible?: boolean): OutputData;
+    _value_getter(json_compatible?: false): OutputData | null;
+    _value_getter(json_compatible: true): JSONCompatibleOutputData | null;
+    _value_getter(json_compatible: boolean): OutputData | JSONCompatibleOutputData | null;
 }
 export declare class DatasetRegion {
     source_dataset: Dataset;
@@ -156,8 +158,10 @@ export declare class DatasetRegion {
     private _metadata?;
     constructor(source_dataset: Dataset, region_reference: RegionReference);
     get metadata(): Metadata;
-    get value(): OutputData;
-    _value_getter(json_compatible?: boolean): OutputData;
+    get value(): OutputData | null;
+    _value_getter(json_compatible?: false): OutputData | null;
+    _value_getter(json_compatible: true): JSONCompatibleOutputData | null;
+    _value_getter(json_compatible: boolean): OutputData | JSONCompatibleOutputData | null;
 }
 export declare const h5wasm: {
     File: typeof File;
diff --git a/src/hdf5_hl.ts b/src/hdf5_hl.ts
index 1fcb494..e862e7c 100644
--- a/src/hdf5_hl.ts
+++ b/src/hdf5_hl.ts
@@ -40,11 +40,15 @@ function dirname(path: string) {
   return head;
 }
 
-function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: true): JSONCompatibleOutputData;
-function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: false): OutputData;
-function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: boolean): OutputData | JSONCompatibleOutputData;
-function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: boolean = false) {
+function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: true): JSONCompatibleOutputData | null;
+function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: false): OutputData | null;
+function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: boolean): OutputData | JSONCompatibleOutputData | null;
+function get_attr(file_id: bigint, obj_name: string, attr_name: string, json_compatible: boolean = false): OutputData | JSONCompatibleOutputData | null {
   let metadata = Module.get_attribute_metadata(file_id, obj_name, attr_name);
+  if (!metadata.shape) {
+    return null;
+  }
+  
   let nbytes = metadata.size * metadata.total_size;
   let data_ptr = Module._malloc(nbytes);
   var processed;
@@ -106,6 +110,7 @@ function process_data(data: Uint8Array, metadata: Metadata, json_compatible: boo
   // but otherwise returns Uint8Array raw bytes as loaded.
   let output_data: OutputData;
   let { shape, type } = metadata;
+
   let known_type = true;
   // let length: number;
   if (type === Module.H5T_class_t.H5T_STRING.value) {
@@ -153,9 +158,9 @@ function process_data(data: Uint8Array, metadata: Metadata, json_compatible: boo
   else if (type === Module.H5T_class_t.H5T_COMPOUND.value) {
     const { size, compound_type } = <{size: Metadata["size"], compound_type: CompoundTypeMetadata}>metadata;
     let n = Math.floor(data.byteLength / size);
-    let output: OutputData[] = [];
+    let output: (OutputData | JSONCompatibleOutputData)[] = [];
     for (let i = 0; i < n; i++) {
-      let row: OutputData = [];
+      let row: (OutputData | JSONCompatibleOutputData)[] = [];
       let row_data = data.slice(i * size, (i + 1) * size);
       for (let member of compound_type.members) {
         let member_data = row_data.slice(member.offset, member.offset + member.size);
@@ -168,7 +173,7 @@ function process_data(data: Uint8Array, metadata: Metadata, json_compatible: boo
 
   else if (type === Module.H5T_class_t.H5T_ARRAY.value) {
     const { array_type } = <{array_type: Metadata}>metadata;
-    shape = shape.concat(array_type.shape);
+    shape = (<number[]>shape).concat(<number[]>array_type.shape);
     array_type.shape = shape;
     // always convert ARRAY types to base JS types:
     output_data = process_data(data, array_type, true);
@@ -220,7 +225,7 @@ function process_data(data: Uint8Array, metadata: Metadata, json_compatible: boo
 }
 
 function isIterable(x: any): x is Iterable<unknown> {
-  return typeof x === 'object' && Symbol.iterator in x;
+  return typeof x === 'object' && x !== null && Symbol.iterator in x;
 }
 
 function isH5PYBooleanEnum(enum_type: EnumTypeMetadata) {
@@ -515,9 +520,9 @@ export class Attribute {
   name: string;
   metadata: Metadata;
   dtype: Dtype;
-  shape: number[];
-  private _value?: OutputData;
-  private _json_value?: JSONCompatibleOutputData;
+  shape: number[] | null;
+  private _value?: OutputData | null;
+  private _json_value?: JSONCompatibleOutputData | null;
 
   constructor(file_id: bigint, path: string, name: string) {
     this.file_id = file_id;
@@ -529,27 +534,27 @@ export class Attribute {
     this.shape = metadata.shape;
   }
 
-  get value() {
+  get value(): OutputData | null {
     if (typeof this._value === "undefined") {
       this._value = get_attr(this.file_id, this.path, this.name, false);
     }
     return this._value;
   }
 
-  get json_value() {
+  get json_value(): JSONCompatibleOutputData | null {
     if (typeof this._json_value === "undefined") {
       this._json_value = get_attr(this.file_id, this.path, this.name, true);
     }
     return this._json_value;
   }
 
-  to_array() {
+  to_array(): JSONCompatibleOutputData | null {
     const { json_value, metadata } = this;
     const { shape } = metadata;
     if (!isIterable(json_value) || typeof json_value === "string") {
       return json_value;
     }
-    return create_nested_array(json_value, shape);
+    return create_nested_array(json_value, <number[]>shape);
   }
 }
 
@@ -916,24 +921,28 @@ export class Dataset extends HasAttrs {
     return Module.get_dataset_filters(this.file_id, this.path);
   }
 
-  get value() {
+  get value(): OutputData | null {
     return this._value_getter(false);
   }
 
-  get json_value(): JSONCompatibleOutputData {
-    return this._value_getter(true) as JSONCompatibleOutputData;
+  get json_value(): JSONCompatibleOutputData | null {
+    return this._value_getter(true);
   }
   
-  slice(ranges: Slice[]) {
+  slice(ranges: Slice[]): OutputData | null {
     // interpret ranges as [start, stop], with one per dim.
     const metadata = this.metadata;
     // if auto_refresh is on, getting the metadata has triggered a refresh of the dataset_id;
     const { shape } = metadata;
+    if (!shape) {
+      return null;
+    }
+
     const {strides, count, offset} = calculateHyperslabParams(shape, ranges);
     const total_size = count.reduce((previous, current) => current * previous, 1n);
     const nbytes = metadata.size * Number(total_size);
     const data_ptr = Module._malloc(nbytes);
-    let processed;
+    let processed: OutputData;
     try {
       Module.get_dataset_data(this.file_id, this.path, count, offset, strides, BigInt(data_ptr));
       let data = Module.HEAPU8.slice(data_ptr, data_ptr + nbytes);
@@ -950,6 +959,9 @@ export class Dataset extends HasAttrs {
   write_slice(ranges: Slice[], data: any) {
     // interpret ranges as [start, stop], with one per dim.
     let metadata = this.metadata;
+    if (!metadata.shape) {
+      throw new Error("cannot write to a slice of an empty dataset");
+    }
     if (metadata.vlen) {
       throw new Error("writing to a slice of vlen dtype is not implemented");
     }
@@ -971,6 +983,10 @@ export class Dataset extends HasAttrs {
 
   create_region_reference(ranges: Slice[]) {
     const metadata = this.metadata;
+    if (!metadata.shape) {
+      throw new Error("cannot create region reference from empty dataset");
+    }
+
     // interpret ranges as [start, stop], with one per dim.
     const { shape } = metadata;
     const {strides, count, offset} = calculateHyperslabParams(shape, ranges);
@@ -978,13 +994,13 @@ export class Dataset extends HasAttrs {
     return new RegionReference(ref_data);
   }
 
-  to_array() {
+  to_array(): JSONCompatibleOutputData | null {
     const { json_value, metadata } = this;
     const { shape } = metadata;
     if (!isIterable(json_value) || typeof json_value === "string") {
       return json_value;
     }
-    let nested =  create_nested_array(json_value, shape);
+    let nested =  create_nested_array(json_value, <number[]>shape);
     return nested;
   }
 
@@ -1033,8 +1049,15 @@ export class Dataset extends HasAttrs {
     return Module.get_dimension_labels(this.file_id, this.path);
   }
 
-  _value_getter(json_compatible=false) {
+  _value_getter(json_compatible?: false): OutputData | null;
+  _value_getter(json_compatible: true): JSONCompatibleOutputData | null;
+  _value_getter(json_compatible: boolean): OutputData | JSONCompatibleOutputData | null;
+  _value_getter(json_compatible=false): OutputData | JSONCompatibleOutputData | null {
     let metadata = this.metadata;
+    if (!metadata.shape) {
+      return null
+    }
+
     // if auto_refresh is on, getting the metadata has triggered a refresh of the dataset_id;
     let nbytes = metadata.size * metadata.total_size;
     let data_ptr = Module._malloc(nbytes);
@@ -1071,12 +1094,19 @@ export class DatasetRegion {
     return this._metadata;
   }
 
-  get value() {
+  get value(): OutputData | null {
     return this._value_getter(false);
   }
 
-  _value_getter(json_compatible=false) {
+  _value_getter(json_compatible?: false): OutputData | null;
+  _value_getter(json_compatible: true): JSONCompatibleOutputData | null;
+  _value_getter(json_compatible: boolean): OutputData | JSONCompatibleOutputData | null;
+  _value_getter(json_compatible=false): OutputData | JSONCompatibleOutputData | null {
     let metadata = this.metadata;
+    if (!metadata.shape) {
+      return null;
+    }
+
     // if auto_refresh is on, getting the metadata has triggered a refresh of the dataset_id;
     let nbytes = metadata.size * metadata.total_size;
     let data_ptr = Module._malloc(nbytes);
@@ -1108,7 +1138,7 @@ function create_nested_array(value: JSONCompatibleOutputData[], shape: number[])
   const subdims = shape.slice(1).reverse();
   for (let dim of subdims) {
     // in each pass, replace input with array of slices of input
-    const new_output: JSONCompatibleOutputData = [];
+    const new_output: JSONCompatibleOutputData[][] = [];
     const { length } = output;
     let cursor = 0;
     while (cursor < length) {
diff --git a/src/hdf5_util.cc b/src/hdf5_util.cc
index 3ea3ea9..1d62227 100644
--- a/src/hdf5_util.cc
+++ b/src/hdf5_util.cc
@@ -345,15 +345,26 @@ val get_abstractDS_metadata(hid_t dspace, hid_t dtype, hid_t dcpl)
 {
     val attr = get_dtype_metadata(dtype);
 
-    int rank = H5Sget_simple_extent_ndims(dspace);
+    int type = H5Sget_simple_extent_type(dspace);
     int total_size = H5Sget_simple_extent_npoints(dspace);
+    attr.set("total_size", total_size);
+
+    if (type == H5S_NULL) {
+        attr.set("shape", val::null());
+        attr.set("maxshape", val::null());
+        attr.set("chunks", val::null());
+        return attr;
+    }
+
+    int rank = H5Sget_simple_extent_ndims(dspace);
     std::vector<hsize_t> dims_out(rank);
     std::vector<hsize_t> maxdims_out(rank);
+
     int ndims = H5Sget_simple_extent_dims(dspace, dims_out.data(), maxdims_out.data());
+
     val shape = val::array();
     val maxshape = val::array();
-    for (int d = 0; d < ndims; d++)
-    {
+    for (int d = 0; d < ndims; d++) {
         shape.set(d, (uint)dims_out.at(d));
         maxshape.set(d, (uint)maxdims_out.at(d));
     }
@@ -364,19 +375,20 @@ val get_abstractDS_metadata(hid_t dspace, hid_t dtype, hid_t dcpl)
 
     if (dcpl) {
         H5D_layout_t layout = H5Pget_layout(dcpl);
+
         if (layout == H5D_CHUNKED) {
             std::vector<hsize_t> chunk_dims_out(ndims);
             H5Pget_chunk(dcpl, ndims, chunk_dims_out.data());
+
             val chunks = val::array();
-            for (int c = 0; c < ndims; c++)
-            {
+            for (int c = 0; c < ndims; c++) {
                 chunks.set(c, (uint)chunk_dims_out.at(c));
             }
+
             attr.set("chunks", chunks);
         }
     }
 
-    attr.set("total_size", total_size);
     return attr;
 }
 
diff --git a/src/hdf5_util_helpers.d.ts b/src/hdf5_util_helpers.d.ts
index 08c85af..f41ab77 100644
--- a/src/hdf5_util_helpers.d.ts
+++ b/src/hdf5_util_helpers.d.ts
@@ -19,14 +19,14 @@ export interface H5T_class_t {
 
 export interface Metadata {
     array_type?: Metadata,
-    chunks: Array<number> | null,
+    chunks: number[] | null,
     compound_type?: CompoundTypeMetadata,
     cset: number,
     enum_type?: EnumTypeMetadata,
     littleEndian: boolean,
-    maxshape: Array<number> | null,
+    maxshape: number[] | null,
     ref_type?: 'object' | 'region',
-    shape: Array<number>,
+    shape: number[] | null,
     signed: boolean,
     size: number,
     total_size: number,
@@ -40,7 +40,7 @@ export interface CompoundMember extends Metadata {
 }
 
 export interface CompoundTypeMetadata {
-    members: Array<CompoundMember>
+    members: CompoundMember[]
     nmembers: number;
 }
 
@@ -105,7 +105,7 @@ export interface H5Module extends EmscriptenModule {
     reclaim_vlen_memory(file_id: BigInt, obj_name: string, attr_name: string, data_ptr: bigint): Status;
     get_attribute_data(file_id: BigInt, obj_name: string, attr_name: string, arg3: bigint): Status;
     FS: FS.FileSystemType,
-    get_keys_vector(group_id: bigint, H5_index_t: number): Array<string>,
+    get_keys_vector(group_id: bigint, H5_index_t: number): string[],
     get_attribute_metadata(loc_id: bigint, group_name_string: string, attribute_name_string: string): Metadata,
     get_plugin_search_paths(): string[],
     insert_plugin_search_path(search_path: string, index: number): number,
@@ -116,7 +116,7 @@ export interface H5Module extends EmscriptenModule {
     get_scale_name(loc_id: bigint, dimscale_dset_name: string): string | null,
     get_attached_scales(loc_id: bigint, target_dset_name: string, index: number): string[],
     set_dimension_label(loc_id: bigint, target_dset_name: string, index: number, label: string): number,
-    get_dimension_labels(loc_id: bigint, target_dset_name: string): Array<string | null>,
+    get_dimension_labels(loc_id: bigint, target_dset_name: string): (string | null)[],
     create_object_reference(loc_id: bigint, target_name: string): Uint8Array,
     create_region_reference(file_id: bigint, path: string, count: bigint[] | null, offset: bigint[] | null, strides: bigint[] | null): Uint8Array,
     get_referenced_name(loc_id: bigint, ref_ptr: Uint8Array, is_object: boolean): string;