diff --git a/internal/engine.cm b/internal/engine.cm
index f491e0fa..f8971208 100644
--- a/internal/engine.cm
+++ b/internal/engine.cm
@@ -158,7 +158,8 @@ function disrupt(err)
   }
 
   if (underlings) {
-    for (var id of underlings) {
+    var unders = array(underlings)
+    for (var id of unders) {
       log.console(`calling on ${id} to disrupt too`)
       $_.stop(create_actor({id}))
     }
@@ -319,7 +320,7 @@ $_.clock = function(fn) {
   })
 }
 
-var underlings = new Set() // this is more like "all actors that are notified when we die"
+var underlings = {} // this is more like "all actors that are notified when we die"
 var overling = null
 var root = null
 
@@ -454,7 +455,7 @@ $_.stop = function stop(actor) {
   }
   if (!is_actor(actor))
     throw Error('Can only call stop on an actor.')
-  if (!underlings.has(actor[ACTORDATA].id))
+  if (is_null(underlings[actor[ACTORDATA].id]))
     throw Error('Can only call stop on an underling or self.')
 
   sys_msg(actor, {kind:"stop"})
@@ -483,10 +484,10 @@ $_.delay = function delay(fn, seconds = 0) {
 var enet = use_core('enet')
 
 // causes this actor to stop when another actor stops.
-var couplings = new Set()
+var couplings = {}
 $_.couple = function couple(actor) {
   if (actor == $_.self) return // can't couple to self
-  couplings.add(actor[ACTORDATA].id)
+  couplings[actor[ACTORDATA].id] = true
   sys_msg(actor, {kind:'couple', from: $_.self})
   log.system(`coupled to ${actor}`)
 }
@@ -676,7 +677,7 @@ function handle_actor_disconnect(id) {
     delete greeters[id]
   }
   log.system(`actor ${id} disconnected`)
-  if (couplings.has(id)) disrupt("coupled actor died") // couplings now disrupts instead of stop
+  if (!is_null(couplings[id])) disrupt("coupled actor died") // couplings now disrupts instead of stop
 }
 
 function handle_sysym(msg)
@@ -691,7 +692,7 @@ function handle_sysym(msg)
       var greeter = greeters[from[ACTORDATA].id]
       if (greeter) greeter(msg.message)
       if (msg.message.type == 'disrupt')
-        underlings.delete(from[ACTORDATA].id)
+        delete underlings[from[ACTORDATA].id]
       break
     case 'contact':
       if (portal_fn) {
@@ -703,7 +704,7 @@ function handle_sysym(msg)
       break
     case 'couple': // from must be notified when we die
       from = msg.from
-      underlings.add(from[ACTORDATA].id)
+      underlings[from[ACTORDATA].id] = true
       log.system(`actor ${from} is coupled to me`)
       break
   }
diff --git a/source/cell.c b/source/cell.c
index 261f9c1b..d41db028 100644
--- a/source/cell.c
+++ b/source/cell.c
@@ -128,7 +128,6 @@ void script_startup(cell_rt *prt)
   JS_AddIntrinsicEval(js);
   JS_AddIntrinsicRegExp(js);
   JS_AddIntrinsicJSON(js);
-  JS_AddIntrinsicMapSet(js);
 
   JS_SetContextOpaque(js, prt);
   prt->context = js;
diff --git a/source/quickjs.c b/source/quickjs.c
index 5eca973b..4b04405a 100644
--- a/source/quickjs.c
+++ b/source/quickjs.c
@@ -170,10 +170,6 @@ enum {
     JS_CLASS_C_FUNCTION_DATA,   /* u.c_function_data_record */
     JS_CLASS_FOR_IN_ITERATOR,   /* u.for_in_iterator */
     JS_CLASS_REGEXP,            /* u.regexp */
-    JS_CLASS_MAP,               /* u.map_state */
-    JS_CLASS_SET,               /* u.map_state */
-    JS_CLASS_MAP_ITERATOR,      /* u.map_iterator_data */
-    JS_CLASS_SET_ITERATOR,      /* u.map_iterator_data */
     JS_CLASS_ARRAY_ITERATOR,    /* u.array_iterator_data */
     JS_CLASS_STRING_ITERATOR,   /* u.array_iterator_data */
     JS_CLASS_REGEXP_STRING_ITERATOR,   /* u.regexp_string_iterator_data */
@@ -831,8 +827,6 @@ struct JSObject {
         struct JSBoundFunction *bound_function; /* JS_CLASS_BOUND_FUNCTION */
         struct JSCFunctionDataRecord *c_function_data_record; /* JS_CLASS_C_FUNCTION_DATA */
         struct JSForInIterator *for_in_iterator; /* JS_CLASS_FOR_IN_ITERATOR */
-        struct JSMapState *map_state;   /* JS_CLASS_MAP..JS_CLASS_WEAKSET */
-        struct JSMapIteratorData *map_iterator_data; /* JS_CLASS_MAP_ITERATOR, JS_CLASS_SET_ITERATOR */
         struct JSArrayIteratorData *array_iterator_data; /* JS_CLASS_ARRAY_ITERATOR, JS_CLASS_STRING_ITERATOR */
         struct JSRegExpStringIteratorData *regexp_string_iterator_data; /* JS_CLASS_REGEXP_STRING_ITERATOR */
         struct { /* JS_CLASS_BYTECODE_FUNCTION: 12/24 bytes */
@@ -861,25 +855,6 @@ struct JSObject {
     } u;
 };
 
-typedef struct JSMapRecord {
-    int ref_count; /* used during enumeration to avoid freeing the record */
-    BOOL empty : 8; /* TRUE if the record is deleted */
-    struct list_head link;
-    struct JSMapRecord *hash_next;
-    JSValue key;
-    JSValue value;
-} JSMapRecord;
-
-typedef struct JSMapState {
-    struct list_head records; /* list of JSMapRecord.link */
-    uint32_t record_count;
-    JSMapRecord **hash_table;
-    int hash_bits;
-    uint32_t hash_size; /* = 2 ^ hash_bits */
-    uint32_t record_count_threshold; /* count at which a hash table
-                                        resize is needed */
-} JSMapState;
-
 enum {
     __JS_ATOM_NULL = JS_ATOM_NULL,
 #define DEF(name, str) JS_ATOM_ ## name,
@@ -983,12 +958,7 @@ static void js_for_in_iterator_finalizer(JSRuntime *rt, JSValue val);
 static void js_for_in_iterator_mark(JSRuntime *rt, JSValueConst val,
                                 JS_MarkFunc *mark_func);
 static void js_regexp_finalizer(JSRuntime *rt, JSValue val);
-static void js_map_finalizer(JSRuntime *rt, JSValue val);
-static void js_map_mark(JSRuntime *rt, JSValueConst val,
-                                JS_MarkFunc *mark_func);
-static void js_map_iterator_finalizer(JSRuntime *rt, JSValue val);
-static void js_map_iterator_mark(JSRuntime *rt, JSValueConst val,
-                                JS_MarkFunc *mark_func);
+
 static void js_array_iterator_finalizer(JSRuntime *rt, JSValue val);
 static void js_array_iterator_mark(JSRuntime *rt, JSValueConst val,
                                 JS_MarkFunc *mark_func);
@@ -1080,8 +1050,6 @@ static void remove_gc_object(JSGCObjectHeader *h);
 static JSValue js_instantiate_prototype(JSContext *ctx, JSObject *p, JSAtom atom, void *opaque);
 static JSValue JS_InstantiateFunctionListItem2(JSContext *ctx, JSObject *p,
                                                JSAtom atom, void *opaque);
-static JSValue js_object_groupBy(JSContext *ctx, JSValueConst this_val,
-                                 int argc, JSValueConst *argv, int is_map);
 static void JS_RunGCInternal(JSRuntime *rt);
 static int js_string_find_invalid_codepoint(JSString *p);
 static JSValue js_regexp_toString(JSContext *ctx, JSValueConst this_val,
@@ -1286,10 +1254,6 @@ static JSClassShortDef const js_std_class_def[] = {
     { JS_ATOM_Function, js_c_function_data_finalizer, js_c_function_data_mark }, /* JS_CLASS_C_FUNCTION_DATA */
     { JS_ATOM_ForInIterator, js_for_in_iterator_finalizer, js_for_in_iterator_mark },      /* JS_CLASS_FOR_IN_ITERATOR */
     { JS_ATOM_RegExp, js_regexp_finalizer, NULL },                              /* JS_CLASS_REGEXP */
-    { JS_ATOM_Map, js_map_finalizer, js_map_mark },             /* JS_CLASS_MAP */
-    { JS_ATOM_Set, js_map_finalizer, js_map_mark },             /* JS_CLASS_SET */
-    { JS_ATOM_Map_Iterator, js_map_iterator_finalizer, js_map_iterator_mark }, /* JS_CLASS_MAP_ITERATOR */
-    { JS_ATOM_Set_Iterator, js_map_iterator_finalizer, js_map_iterator_mark }, /* JS_CLASS_SET_ITERATOR */
     { JS_ATOM_Array_Iterator, js_array_iterator_finalizer, js_array_iterator_mark }, /* JS_CLASS_ARRAY_ITERATOR */
     { JS_ATOM_String_Iterator, js_array_iterator_finalizer, js_array_iterator_mark }, /* JS_CLASS_STRING_ITERATOR */
     { JS_ATOM_RegExp_String_Iterator, js_regexp_string_iterator_finalizer, js_regexp_string_iterator_mark }, /* JS_CLASS_REGEXP_STRING_ITERATOR */
@@ -1939,7 +1903,6 @@ JSContext *JS_NewContext(JSRuntime *rt)
     JS_AddIntrinsicEval(ctx);
     JS_AddIntrinsicStringNormalize(ctx);
     JS_AddIntrinsicRegExp(ctx);
-    JS_AddIntrinsicMapSet(ctx);
 
     return ctx;
 }
@@ -6025,10 +5988,6 @@ void JS_ComputeMemoryUsage(JSRuntime *rt, JSMemoryUsage *s)
                 }
             }
             break;
-        case JS_CLASS_MAP:               /* u.map_state */
-        case JS_CLASS_SET:               /* u.map_state */
-        case JS_CLASS_MAP_ITERATOR:      /* u.map_iterator_data */
-        case JS_CLASS_SET_ITERATOR:      /* u.map_iterator_data */
         case JS_CLASS_ARRAY_ITERATOR:    /* u.array_iterator_data */
         case JS_CLASS_STRING_ITERATOR:   /* u.array_iterator_data */
             /* TODO */
@@ -10619,31 +10578,6 @@ static void js_print_object(JSPrintValueState *s, JSObject *p)
         }
         js_printf(s, "]");
         comma_state = 2;
-    } else if (p->class_id == JS_CLASS_MAP || p->class_id == JS_CLASS_SET) {
-        JSMapState *ms = p->u.opaque;
-        struct list_head *el;
-        
-        if (!ms)
-            goto default_obj;
-        js_print_atom(s, rt->class_array[p->class_id].class_name);
-        js_printf(s, "(%u) { ", ms->record_count);
-        i = 0;
-        list_for_each(el, &ms->records) {
-            JSMapRecord *mr = list_entry(el, JSMapRecord, link);
-            js_print_comma(s, &comma_state);
-            if (mr->empty)
-                continue;
-            js_print_value(s, mr->key);
-            if (p->class_id == JS_CLASS_MAP) {
-                js_printf(s, " => ");
-                js_print_value(s, mr->value);
-            }
-            i++;
-            if (i >= s->options.max_item_count)
-                break;
-        }
-        if (i < ms->record_count)
-            js_print_more_items(s, &comma_state, ms->record_count - i);
     } else if (p->class_id == JS_CLASS_REGEXP && s->ctx && !s->options.raw_dump) {
         JSValue str = js_regexp_toString(s->ctx, JS_MKPTR(JS_TAG_OBJECT, p), 0, NULL);
         if (JS_IsException(str))
@@ -29141,7 +29075,6 @@ static const JSCFunctionListEntry js_object_funcs[] = {
     JS_CFUNC_MAGIC_DEF("defineProperty", 3, js_object_defineProperty, 0 ),
     JS_CFUNC_DEF("defineProperties", 2, js_object_defineProperties ),
     JS_CFUNC_DEF("getOwnPropertyNames", 1, js_object_getOwnPropertyNames ),
-    JS_CFUNC_MAGIC_DEF("groupBy", 2, js_object_groupBy, 0 ),
     JS_CFUNC_MAGIC_DEF("isExtensible", 1, js_object_isExtensible, 0 ),
     JS_CFUNC_MAGIC_DEF("preventExtensions", 1, js_object_preventExtensions, 0 ),
     JS_CFUNC_MAGIC_DEF("getOwnPropertyDescriptor", 2, js_object_getOwnPropertyDescriptor, 0 ),
@@ -35482,847 +35415,6 @@ static const JSCFunctionListEntry js_symbol_proto_funcs[] = {
     JS_CGETSET_DEF("description", js_symbol_get_description, NULL ),
 };
 
-/* Set/Map/WeakSet/WeakMap */
-
-#define MAGIC_SET (1 << 0)
-
-static JSValue js_map_constructor(JSContext *ctx, JSValueConst new_target,
-                                  int argc, JSValueConst *argv, int magic)
-{
-
-    JSMapState *s;
-    JSValue obj, adder = JS_NULL, iter = JS_NULL, next_method = JS_NULL;
-    JSValueConst arr;
-    BOOL is_set;
-
-    is_set = magic & MAGIC_SET;
-    obj = js_create_from_ctor(ctx, new_target, JS_CLASS_MAP + magic);
-    if (JS_IsException(obj))
-        return JS_EXCEPTION;
-    s = js_mallocz(ctx, sizeof(*s));
-    if (!s)
-        goto fail;
-    init_list_head(&s->records);
-    JS_SetOpaque(obj, s);
-    s->hash_bits = 1;
-    s->hash_size = 1U << s->hash_bits;
-    s->hash_table = js_mallocz(ctx, sizeof(s->hash_table[0]) * s->hash_size);
-    if (!s->hash_table)
-        goto fail;
-    s->record_count_threshold = 4;
-
-    arr = JS_NULL;
-    if (argc > 0)
-        arr = argv[0];
-    if (!JS_IsNull(arr) && !JS_IsNull(arr)) {
-        JSValue item, ret;
-        BOOL done;
-
-        adder = JS_GetProperty(ctx, obj, is_set ? JS_ATOM_add : JS_ATOM_set);
-        if (JS_IsException(adder))
-            goto fail;
-        if (!JS_IsFunction(ctx, adder)) {
-            JS_ThrowTypeError(ctx, "set/add is not a function");
-            goto fail;
-        }
-
-        iter = JS_GetIterator(ctx, arr);
-        if (JS_IsException(iter))
-            goto fail;
-        next_method = JS_GetProperty(ctx, iter, JS_ATOM_next);
-        if (JS_IsException(next_method))
-            goto fail;
-
-        for(;;) {
-            item = JS_IteratorNext(ctx, iter, next_method, 0, NULL, &done);
-            if (JS_IsException(item))
-                goto fail;
-            if (done)
-                break;
-            if (is_set) {
-                ret = JS_Call(ctx, adder, obj, 1, (JSValueConst *)&item);
-                if (JS_IsException(ret)) {
-                    JS_FreeValue(ctx, item);
-                    goto fail_close;
-                }
-            } else {
-                JSValue key, value;
-                JSValueConst args[2];
-                key = JS_NULL;
-                value = JS_NULL;
-                if (!JS_IsObject(item)) {
-                    JS_ThrowTypeErrorNotAnObject(ctx);
-                    goto fail1;
-                }
-                key = JS_GetPropertyUint32(ctx, item, 0);
-                if (JS_IsException(key))
-                    goto fail1;
-                value = JS_GetPropertyUint32(ctx, item, 1);
-                if (JS_IsException(value))
-                    goto fail1;
-                args[0] = key;
-                args[1] = value;
-                ret = JS_Call(ctx, adder, obj, 2, args);
-                if (JS_IsException(ret)) {
-                fail1:
-                    JS_FreeValue(ctx, item);
-                    JS_FreeValue(ctx, key);
-                    JS_FreeValue(ctx, value);
-                    goto fail_close;
-                }
-                JS_FreeValue(ctx, key);
-                JS_FreeValue(ctx, value);
-            }
-            JS_FreeValue(ctx, ret);
-            JS_FreeValue(ctx, item);
-        }
-        JS_FreeValue(ctx, next_method);
-        JS_FreeValue(ctx, iter);
-        JS_FreeValue(ctx, adder);
-    }
-
-    return obj;
- fail_close:
-    /* close the iterator object, preserving pending exception */
-    JS_IteratorClose(ctx, iter, TRUE);
- fail:
-
-    JS_FreeValue(ctx, next_method);
-    JS_FreeValue(ctx, iter);
-    JS_FreeValue(ctx, adder);
-    JS_FreeValue(ctx, obj);
-    return JS_EXCEPTION;
-}
-
-/* XXX: could normalize strings to speed up comparison */
-static JSValueConst map_normalize_key(JSContext *ctx, JSValueConst key)
-{
-    uint32_t tag = JS_VALUE_GET_TAG(key);
-    /* convert -0.0 to +0.0 */
-    if (JS_TAG_IS_FLOAT64(tag) && JS_VALUE_GET_FLOAT64(key) == 0.0) {
-        key = JS_NewInt32(ctx, 0);
-    }
-    return key;
-}
-
-/* hash multipliers, same as the Linux kernel (see Knuth vol 3,
-   section 6.4, exercise 9) */
-#define HASH_MUL32 0x61C88647
-#define HASH_MUL64 UINT64_C(0x61C8864680B583EB)
-
-static uint32_t map_hash32(uint32_t a, int hash_bits)
-{
-    return (a * HASH_MUL32) >> (32 - hash_bits);
-}
-
-static uint32_t map_hash64(uint64_t a, int hash_bits)
-{
-    return (a * HASH_MUL64) >> (64 - hash_bits);
-}
-
-static uint32_t map_hash_pointer(uintptr_t a, int hash_bits)
-{
-#ifdef JS_PTR64
-    return map_hash64(a, hash_bits);
-#else
-    return map_hash32(a, hash_bits);
-#endif
-}
-
-/* XXX: better hash ? */
-/* precondition: 1 <= hash_bits <= 32 */
-static uint32_t map_hash_key(JSValueConst key, int hash_bits)
-{
-    uint32_t tag = JS_VALUE_GET_NORM_TAG(key);
-    uint32_t h;
-    double d;
-    
-    switch(tag) {
-    case JS_TAG_BOOL:
-        h = map_hash32(JS_VALUE_GET_INT(key) ^ JS_TAG_BOOL, hash_bits);
-        break;
-    case JS_TAG_STRING:
-        h = map_hash32(hash_string(JS_VALUE_GET_STRING(key), 0) ^ JS_TAG_STRING, hash_bits);
-        break;
-    case JS_TAG_STRING_ROPE:
-        h = map_hash32(hash_string_rope(key, 0) ^ JS_TAG_STRING, hash_bits);
-        break;
-    case JS_TAG_OBJECT:
-    case JS_TAG_SYMBOL:
-        h = map_hash_pointer((uintptr_t)JS_VALUE_GET_PTR(key) ^ tag, hash_bits);
-        break;
-    case JS_TAG_INT:
-        d = JS_VALUE_GET_INT(key);
-        goto hash_float64;
-    case JS_TAG_FLOAT64:
-        d = JS_VALUE_GET_FLOAT64(key);
-        /* normalize the NaN */
-        if (isnan(d))
-            d = JS_FLOAT64_NAN;
-    hash_float64:
-        h = map_hash64(float64_as_uint64(d) ^ JS_TAG_FLOAT64, hash_bits);
-        break;
-    default:
-        h = 0;
-        break;
-    }
-    return h;
-}
-
-static JSMapRecord *map_find_record(JSContext *ctx, JSMapState *s,
-                                    JSValueConst key)
-{
-    JSMapRecord *mr;
-    uint32_t h;
-    h = map_hash_key(key, s->hash_bits);
-    for(mr = s->hash_table[h]; mr != NULL; mr = mr->hash_next) {
-        if (mr->empty) {
-            /* cannot match */
-        } else {
-            if (js_same_value_zero(ctx, mr->key, key))
-                return mr;
-        }
-    }
-    return NULL;
-}
-
-static void map_hash_resize(JSContext *ctx, JSMapState *s)
-{
-    uint32_t new_hash_size, h;
-    int new_hash_bits;
-    struct list_head *el;
-    JSMapRecord *mr, **new_hash_table;
-
-    /* XXX: no reporting of memory allocation failure */
-    new_hash_bits = min_int(s->hash_bits + 1, 31);
-    new_hash_size = 1U << new_hash_bits;
-    new_hash_table = js_realloc(ctx, s->hash_table,
-                                sizeof(new_hash_table[0]) * new_hash_size);
-    if (!new_hash_table)
-        return;
-
-    memset(new_hash_table, 0, sizeof(new_hash_table[0]) * new_hash_size);
-
-    list_for_each(el, &s->records) {
-        mr = list_entry(el, JSMapRecord, link);
-        if (mr->empty) {
-        } else {
-            h = map_hash_key(mr->key, new_hash_bits);
-            mr->hash_next = new_hash_table[h];
-            new_hash_table[h] = mr;
-        }
-    }
-    s->hash_table = new_hash_table;
-    s->hash_bits = new_hash_bits;
-    s->hash_size = new_hash_size;
-    s->record_count_threshold = new_hash_size * 2;
-}
-
-static JSMapRecord *map_add_record(JSContext *ctx, JSMapState *s,
-                                   JSValueConst key)
-{
-    uint32_t h;
-    JSMapRecord *mr;
-
-    mr = js_malloc(ctx, sizeof(*mr));
-    if (!mr)
-        return NULL;
-    mr->ref_count = 1;
-    mr->empty = FALSE;
-    mr->key = JS_DupValue(ctx, key);
-    h = map_hash_key(key, s->hash_bits);
-    mr->hash_next = s->hash_table[h];
-    s->hash_table[h] = mr;
-    list_add_tail(&mr->link, &s->records);
-    s->record_count++;
-    if (s->record_count >= s->record_count_threshold) {
-        map_hash_resize(ctx, s);
-    }
-    return mr;
-}
-
-/* warning: the record must be removed from the hash table before */
-static void map_delete_record(JSRuntime *rt, JSMapState *s, JSMapRecord *mr)
-{
-    if (mr->empty)
-        return;
-    
-    JS_FreeValueRT(rt, mr->key);
-    JS_FreeValueRT(rt, mr->value);
-    if (--mr->ref_count == 0) {
-        list_del(&mr->link);
-        js_free_rt(rt, mr);
-    } else {
-        /* keep a zombie record for iterators */
-        mr->empty = TRUE;
-        mr->key = JS_NULL;
-        mr->value = JS_NULL;
-    }
-    s->record_count--;
-}
-
-static void map_decref_record(JSRuntime *rt, JSMapRecord *mr)
-{
-    if (--mr->ref_count == 0) {
-        /* the record can be safely removed */
-        assert(mr->empty);
-        list_del(&mr->link);
-        js_free_rt(rt, mr);
-    }
-}
-
-static JSValue js_map_set(JSContext *ctx, JSValueConst this_val,
-                          int argc, JSValueConst *argv, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    JSMapRecord *mr;
-    JSValueConst key, value;
-
-    if (!s)
-        return JS_EXCEPTION;
-    key = map_normalize_key(ctx, argv[0]);
-    if (magic & MAGIC_SET)
-        value = JS_NULL;
-    else
-        value = argv[1];
-    mr = map_find_record(ctx, s, key);
-    if (mr) {
-        JS_FreeValue(ctx, mr->value);
-    } else {
-        mr = map_add_record(ctx, s, key);
-        if (!mr)
-            return JS_EXCEPTION;
-    }
-    mr->value = JS_DupValue(ctx, value);
-    return JS_DupValue(ctx, this_val);
-}
-
-static JSValue js_map_get(JSContext *ctx, JSValueConst this_val,
-                          int argc, JSValueConst *argv, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    JSMapRecord *mr;
-    JSValueConst key;
-
-    if (!s)
-        return JS_EXCEPTION;
-    key = map_normalize_key(ctx, argv[0]);
-    mr = map_find_record(ctx, s, key);
-    if (!mr)
-        return JS_NULL;
-    else
-        return JS_DupValue(ctx, mr->value);
-}
-
-static JSValue js_map_has(JSContext *ctx, JSValueConst this_val,
-                          int argc, JSValueConst *argv, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    JSMapRecord *mr;
-    JSValueConst key;
-
-    if (!s)
-        return JS_EXCEPTION;
-    key = map_normalize_key(ctx, argv[0]);
-    mr = map_find_record(ctx, s, key);
-    return JS_NewBool(ctx, mr != NULL);
-}
-
-static JSValue js_map_delete(JSContext *ctx, JSValueConst this_val,
-                             int argc, JSValueConst *argv, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    JSMapRecord *mr, **pmr;
-    JSValueConst key;
-    uint32_t h;
-
-    if (!s)
-        return JS_EXCEPTION;
-    key = map_normalize_key(ctx, argv[0]);
-    
-    h = map_hash_key(key, s->hash_bits);
-    pmr = &s->hash_table[h];
-    for(;;) {
-        mr = *pmr;
-        if (mr == NULL)
-            return JS_FALSE;
-        if (mr->empty) {
-            /* not valid */
-        } else {
-            if (js_same_value_zero(ctx, mr->key, key))
-                break;
-        }
-        pmr = &mr->hash_next;
-    }
-
-    /* remove from the hash table */
-    *pmr = mr->hash_next;
-    
-    map_delete_record(ctx->rt, s, mr);
-    return JS_TRUE;
-}
-
-static JSValue js_map_clear(JSContext *ctx, JSValueConst this_val,
-                            int argc, JSValueConst *argv, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    struct list_head *el, *el1;
-    JSMapRecord *mr;
-
-    if (!s)
-        return JS_EXCEPTION;
-
-    /* remove from the hash table */
-    memset(s->hash_table, 0, sizeof(s->hash_table[0]) * s->hash_size);
-    
-    list_for_each_safe(el, el1, &s->records) {
-        mr = list_entry(el, JSMapRecord, link);
-        map_delete_record(ctx->rt, s, mr);
-    }
-    return JS_NULL;
-}
-
-static JSValue js_map_get_size(JSContext *ctx, JSValueConst this_val, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    if (!s)
-        return JS_EXCEPTION;
-    return JS_NewUint32(ctx, s->record_count);
-}
-
-static JSValue js_map_forEach(JSContext *ctx, JSValueConst this_val,
-                              int argc, JSValueConst *argv, int magic)
-{
-    JSMapState *s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    JSValueConst func, this_arg;
-    JSValue ret, args[3];
-    struct list_head *el;
-    JSMapRecord *mr;
-
-    if (!s)
-        return JS_EXCEPTION;
-    func = argv[0];
-    if (argc > 1)
-        this_arg = argv[1];
-    else
-        this_arg = JS_NULL;
-    if (check_function(ctx, func))
-        return JS_EXCEPTION;
-    /* Note: the list can be modified while traversing it, but the
-       current element is locked */
-    el = s->records.next;
-    while (el != &s->records) {
-        mr = list_entry(el, JSMapRecord, link);
-        if (!mr->empty) {
-            mr->ref_count++;
-            /* must duplicate in case the record is deleted */
-            args[1] = JS_DupValue(ctx, mr->key);
-            if (magic)
-                args[0] = args[1];
-            else
-                args[0] = JS_DupValue(ctx, mr->value);
-            args[2] = (JSValue)this_val;
-            ret = JS_Call(ctx, func, this_arg, 3, (JSValueConst *)args);
-            JS_FreeValue(ctx, args[0]);
-            if (!magic)
-                JS_FreeValue(ctx, args[1]);
-            el = el->next;
-            map_decref_record(ctx->rt, mr);
-            if (JS_IsException(ret))
-                return ret;
-            JS_FreeValue(ctx, ret);
-        } else {
-            el = el->next;
-        }
-    }
-    return JS_NULL;
-}
-
-static JSValue js_object_groupBy(JSContext *ctx, JSValueConst this_val,
-                                 int argc, JSValueConst *argv, int is_map)
-{
-    JSValueConst cb, args[2];
-    JSValue res, iter, next, groups, key, v, prop;
-    JSAtom key_atom = JS_ATOM_NULL;
-    int64_t idx;
-    BOOL done;
-
-    // "is function?" check must be observed before argv[0] is accessed
-    cb = argv[1];
-    if (check_function(ctx, cb))
-        return JS_EXCEPTION;
-
-    iter = JS_GetIterator(ctx, argv[0]);
-    if (JS_IsException(iter))
-        return JS_EXCEPTION;
-
-    key = JS_NULL;
-    key_atom = JS_ATOM_NULL;
-    v = JS_NULL;
-    prop = JS_NULL;
-    groups = JS_NULL;
-
-    next = JS_GetProperty(ctx, iter, JS_ATOM_next);
-    if (JS_IsException(next))
-        goto exception;
-
-    if (is_map) {
-        groups = js_map_constructor(ctx, JS_NULL, 0, NULL, 0);
-    } else {
-        groups = JS_NewObjectProto(ctx, JS_NULL);
-    }
-    if (JS_IsException(groups))
-        goto exception;
-
-    for (idx = 0; ; idx++) {
-        if (idx >= MAX_SAFE_INTEGER) {
-            JS_ThrowTypeError(ctx, "too many elements");
-            goto iterator_close_exception;
-        }
-        v = JS_IteratorNext(ctx, iter, next, 0, NULL, &done);
-        if (JS_IsException(v))
-            goto exception;
-        if (done)
-            break; // v is JS_NULL
-
-        args[0] = v;
-        args[1] = JS_NewInt64(ctx, idx);
-        key = JS_Call(ctx, cb, ctx->global_obj, 2, args);
-        if (JS_IsException(key))
-            goto iterator_close_exception;
-
-        if (is_map) {
-            prop = js_map_get(ctx, groups, 1, (JSValueConst *)&key, 0);
-        } else {
-            key_atom = JS_ValueToAtom(ctx, key);
-            JS_FreeValue(ctx, key);
-            key = JS_NULL;
-            if (key_atom == JS_ATOM_NULL)
-                goto iterator_close_exception;
-            prop = JS_GetProperty(ctx, groups, key_atom);
-        }
-        if (JS_IsException(prop))
-            goto exception;
-
-        if (JS_IsNull(prop)) {
-            prop = JS_NewArray(ctx);
-            if (JS_IsException(prop))
-                goto exception;
-            if (is_map) {
-                args[0] = key;
-                args[1] = prop;
-                res = js_map_set(ctx, groups, 2, args, 0);
-                if (JS_IsException(res))
-                    goto exception;
-                JS_FreeValue(ctx, res);
-            } else {
-                prop = JS_DupValue(ctx, prop);
-                if (JS_DefinePropertyValue(ctx, groups, key_atom, prop,
-                                           JS_PROP_C_W_E) < 0) {
-                    goto exception;
-                }
-            }
-        }
-        res = js_array_push(ctx, prop, 1, (JSValueConst *)&v, /*unshift*/0);
-        if (JS_IsException(res))
-            goto exception;
-        // res is an int64
-
-        JS_FreeValue(ctx, prop);
-        JS_FreeValue(ctx, key);
-        JS_FreeAtom(ctx, key_atom);
-        JS_FreeValue(ctx, v);
-        prop = JS_NULL;
-        key = JS_NULL;
-        key_atom = JS_ATOM_NULL;
-        v = JS_NULL;
-    }
-
-    JS_FreeValue(ctx, iter);
-    JS_FreeValue(ctx, next);
-    return groups;
-
- iterator_close_exception:
-    JS_IteratorClose(ctx, iter, TRUE);
- exception:
-    JS_FreeAtom(ctx, key_atom);
-    JS_FreeValue(ctx, prop);
-    JS_FreeValue(ctx, key);
-    JS_FreeValue(ctx, v);
-    JS_FreeValue(ctx, groups);
-    JS_FreeValue(ctx, iter);
-    JS_FreeValue(ctx, next);
-    return JS_EXCEPTION;
-}
-
-static void js_map_finalizer(JSRuntime *rt, JSValue val)
-{
-    JSObject *p;
-    JSMapState *s;
-    struct list_head *el, *el1;
-    JSMapRecord *mr;
-
-    p = JS_VALUE_GET_OBJ(val);
-    s = p->u.map_state;
-    if (s) {
-        /* if the object is deleted we are sure that no iterator is
-           using it */
-        list_for_each_safe(el, el1, &s->records) {
-            mr = list_entry(el, JSMapRecord, link);
-            if (!mr->empty) {
-                JS_FreeValueRT(rt, mr->key);
-                JS_FreeValueRT(rt, mr->value);
-            }
-            js_free_rt(rt, mr);
-        }
-        js_free_rt(rt, s->hash_table);
-        js_free_rt(rt, s);
-    }
-}
-
-static void js_map_mark(JSRuntime *rt, JSValueConst val, JS_MarkFunc *mark_func)
-{
-    JSObject *p = JS_VALUE_GET_OBJ(val);
-    JSMapState *s;
-    struct list_head *el;
-    JSMapRecord *mr;
-
-    s = p->u.map_state;
-    if (s) {
-        list_for_each(el, &s->records) {
-            mr = list_entry(el, JSMapRecord, link);
-            JS_MarkValue(rt, mr->key, mark_func);
-            JS_MarkValue(rt, mr->value, mark_func);
-        }
-    }
-}
-
-/* Map Iterator */
-
-typedef struct JSMapIteratorData {
-    JSValue obj;
-    JSIteratorKindEnum kind;
-    JSMapRecord *cur_record;
-} JSMapIteratorData;
-
-static void js_map_iterator_finalizer(JSRuntime *rt, JSValue val)
-{
-    JSObject *p;
-    JSMapIteratorData *it;
-
-    p = JS_VALUE_GET_OBJ(val);
-    it = p->u.map_iterator_data;
-    if (it) {
-        /* During the GC sweep phase the Map finalizer may be
-           called before the Map iterator finalizer */
-        if (JS_IsLiveObject(rt, it->obj) && it->cur_record) {
-            map_decref_record(rt, it->cur_record);
-        }
-        JS_FreeValueRT(rt, it->obj);
-        js_free_rt(rt, it);
-    }
-}
-
-static void js_map_iterator_mark(JSRuntime *rt, JSValueConst val,
-                                 JS_MarkFunc *mark_func)
-{
-    JSObject *p = JS_VALUE_GET_OBJ(val);
-    JSMapIteratorData *it;
-    it = p->u.map_iterator_data;
-    if (it) {
-        /* the record is already marked by the object */
-        JS_MarkValue(rt, it->obj, mark_func);
-    }
-}
-
-static JSValue js_create_map_iterator(JSContext *ctx, JSValueConst this_val,
-                                      int argc, JSValueConst *argv, int magic)
-{
-    JSIteratorKindEnum kind;
-    JSMapState *s;
-    JSMapIteratorData *it;
-    JSValue enum_obj;
-
-    kind = magic >> 2;
-    magic &= 3;
-    s = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP + magic);
-    if (!s)
-        return JS_EXCEPTION;
-    enum_obj = JS_NewObjectClass(ctx, JS_CLASS_MAP_ITERATOR + magic);
-    if (JS_IsException(enum_obj))
-        goto fail;
-    it = js_malloc(ctx, sizeof(*it));
-    if (!it) {
-        JS_FreeValue(ctx, enum_obj);
-        goto fail;
-    }
-    it->obj = JS_DupValue(ctx, this_val);
-    it->kind = kind;
-    it->cur_record = NULL;
-    JS_SetOpaque(enum_obj, it);
-    return enum_obj;
- fail:
-    return JS_EXCEPTION;
-}
-
-static JSValue js_map_iterator_next(JSContext *ctx, JSValueConst this_val,
-                                    int argc, JSValueConst *argv,
-                                    BOOL *pdone, int magic)
-{
-    JSMapIteratorData *it;
-    JSMapState *s;
-    JSMapRecord *mr;
-    struct list_head *el;
-
-    it = JS_GetOpaque2(ctx, this_val, JS_CLASS_MAP_ITERATOR + magic);
-    if (!it) {
-        *pdone = FALSE;
-        return JS_EXCEPTION;
-    }
-    if (JS_IsNull(it->obj))
-        goto done;
-    s = JS_GetOpaque(it->obj, JS_CLASS_MAP + magic);
-    assert(s != NULL);
-    if (!it->cur_record) {
-        el = s->records.next;
-    } else {
-        mr = it->cur_record;
-        el = mr->link.next;
-        map_decref_record(ctx->rt, mr); /* the record can be freed here */
-    }
-    for(;;) {
-        if (el == &s->records) {
-            /* no more record  */
-            it->cur_record = NULL;
-            JS_FreeValue(ctx, it->obj);
-            it->obj = JS_NULL;
-        done:
-            /* end of enumeration */
-            *pdone = TRUE;
-            return JS_NULL;
-        }
-        mr = list_entry(el, JSMapRecord, link);
-        if (!mr->empty)
-            break;
-        /* get the next record */
-        el = mr->link.next;
-    }
-
-    /* lock the record so that it won't be freed */
-    mr->ref_count++;
-    it->cur_record = mr;
-    *pdone = FALSE;
-
-    if (it->kind == JS_ITERATOR_KIND_KEY) {
-        return JS_DupValue(ctx, mr->key);
-    } else {
-        JSValueConst args[2];
-        args[0] = mr->key;
-        if (magic)
-            args[1] = mr->key;
-        else
-            args[1] = mr->value;
-        if (it->kind == JS_ITERATOR_KIND_VALUE) {
-            return JS_DupValue(ctx, args[1]);
-        } else {
-            return js_create_array(ctx, 2, args);
-        }
-    }
-}
-
-static const JSCFunctionListEntry js_map_funcs[] = {
-    JS_CFUNC_MAGIC_DEF("groupBy", 2, js_object_groupBy, 1 ),
-    JS_CGETSET_DEF("[Symbol.species]", js_get_this, NULL ),
-};
-
-static const JSCFunctionListEntry js_map_proto_funcs[] = {
-    JS_CFUNC_MAGIC_DEF("set", 2, js_map_set, 0 ),
-    JS_CFUNC_MAGIC_DEF("get", 1, js_map_get, 0 ),
-    JS_CFUNC_MAGIC_DEF("has", 1, js_map_has, 0 ),
-    JS_CFUNC_MAGIC_DEF("delete", 1, js_map_delete, 0 ),
-    JS_CFUNC_MAGIC_DEF("clear", 0, js_map_clear, 0 ),
-    JS_CGETSET_MAGIC_DEF("size", js_map_get_size, NULL, 0),
-    JS_CFUNC_MAGIC_DEF("forEach", 1, js_map_forEach, 0 ),
-    JS_CFUNC_MAGIC_DEF("values", 0, js_create_map_iterator, (JS_ITERATOR_KIND_VALUE << 2) | 0 ),
-    JS_CFUNC_MAGIC_DEF("keys", 0, js_create_map_iterator, (JS_ITERATOR_KIND_KEY << 2) | 0 ),
-    JS_CFUNC_MAGIC_DEF("entries", 0, js_create_map_iterator, (JS_ITERATOR_KIND_KEY_AND_VALUE << 2) | 0 ),
-    JS_ALIAS_DEF("[Symbol.iterator]", "entries" ),
-    JS_PROP_STRING_DEF("[Symbol.toStringTag]", "Map", JS_PROP_CONFIGURABLE ),
-};
-
-static const JSCFunctionListEntry js_map_iterator_proto_funcs[] = {
-    JS_ITERATOR_NEXT_DEF("next", 0, js_map_iterator_next, 0 ),
-    JS_PROP_STRING_DEF("[Symbol.toStringTag]", "Map Iterator", JS_PROP_CONFIGURABLE ),
-};
-
-static const JSCFunctionListEntry js_set_proto_funcs[] = {
-    JS_CFUNC_MAGIC_DEF("add", 1, js_map_set, MAGIC_SET ),
-    JS_CFUNC_MAGIC_DEF("has", 1, js_map_has, MAGIC_SET ),
-    JS_CFUNC_MAGIC_DEF("delete", 1, js_map_delete, MAGIC_SET ),
-    JS_CFUNC_MAGIC_DEF("clear", 0, js_map_clear, MAGIC_SET ),
-    JS_CGETSET_MAGIC_DEF("size", js_map_get_size, NULL, MAGIC_SET ),
-    JS_CFUNC_MAGIC_DEF("forEach", 1, js_map_forEach, MAGIC_SET ),
-    JS_CFUNC_MAGIC_DEF("values", 0, js_create_map_iterator, (JS_ITERATOR_KIND_KEY << 2) | MAGIC_SET ),
-    JS_ALIAS_DEF("keys", "values" ),
-    JS_ALIAS_DEF("[Symbol.iterator]", "values" ),
-    JS_CFUNC_MAGIC_DEF("entries", 0, js_create_map_iterator, (JS_ITERATOR_KIND_KEY_AND_VALUE << 2) | MAGIC_SET ),
-    JS_PROP_STRING_DEF("[Symbol.toStringTag]", "Set", JS_PROP_CONFIGURABLE ),
-};
-
-static const JSCFunctionListEntry js_set_iterator_proto_funcs[] = {
-    JS_ITERATOR_NEXT_DEF("next", 0, js_map_iterator_next, MAGIC_SET ),
-    JS_PROP_STRING_DEF("[Symbol.toStringTag]", "Set Iterator", JS_PROP_CONFIGURABLE ),
-};
-
-static const JSCFunctionListEntry * const js_map_proto_funcs_ptr[4] = {
-    js_map_proto_funcs,
-    js_set_proto_funcs,
-    js_map_iterator_proto_funcs,
-    js_set_iterator_proto_funcs,
-};
-
-static const uint8_t js_map_proto_funcs_count[4] = {
-    countof(js_map_proto_funcs),
-    countof(js_set_proto_funcs),
-    countof(js_map_iterator_proto_funcs),
-    countof(js_set_iterator_proto_funcs),
-};
-
-void JS_AddIntrinsicMapSet(JSContext *ctx)
-{
-  int i;
-  JSValue obj1;
-  char buf[ATOM_GET_STR_BUF_SIZE];
-
-  /* --- Map and Set --- */
-  for(i = 0; i < 2; i++) {
-    const char *name = JS_AtomGetStr(ctx, buf, sizeof(buf),
-                                     JS_ATOM_Map + i);
-    ctx->class_proto[JS_CLASS_MAP + i] = JS_NewObject(ctx);
-    JS_SetPropertyFunctionList(ctx,
-        ctx->class_proto[JS_CLASS_MAP + i],
-        js_map_proto_funcs_ptr[i],
-        js_map_proto_funcs_count[i]);
-    obj1 = JS_NewCFunctionMagic(ctx, js_map_constructor, name,
-        0, JS_CFUNC_constructor_magic, i);
-    JS_SetPropertyFunctionList(ctx, obj1,
-        js_map_funcs, countof(js_map_funcs));
-    JS_NewGlobalCConstructor2(ctx, obj1, name,
-        ctx->class_proto[JS_CLASS_MAP + i]);
-  }
-
-  /* --- MapIterator and SetIterator --- */
-  for(i = 0; i < 2; i++) {
-    ctx->class_proto[JS_CLASS_MAP_ITERATOR + i] =
-      JS_NewObjectProto(ctx, ctx->iterator_proto);
-    JS_SetPropertyFunctionList(ctx,
-        ctx->class_proto[JS_CLASS_MAP_ITERATOR + i],
-        /* now offset by +2, not +4 */    
-        js_map_proto_funcs_ptr[i + 2],
-        js_map_proto_funcs_count[i + 2]);
-  }
-}
-
 /* global object */
 
 /* ============================================================================
@@ -36336,7 +35428,6 @@ void JS_AddIntrinsicMapSet(JSContext *ctx)
  * - fn: function utilities
  * ============================================================================ */
 
-
 /* ----------------------------------------------------------------------------
  * number function and sub-functions
  * ---------------------------------------------------------------------------- */
@@ -37769,45 +36860,6 @@ static JSValue js_cell_array(JSContext *ctx, JSValueConst this_val,
 
   /* array(object) - keys */
   if (JS_IsObject(arg) && !JS_IsArray(ctx, arg)) {
-    /* Check if it's a Set */
-    JSObject *p = JS_VALUE_GET_OBJ(arg);
-    if (p->class_id == JS_CLASS_SET) {
-      /* Convert Set to array */
-      JSValue iter = JS_GetProperty(ctx, arg, JS_ATOM_Symbol_iterator);
-      if (JS_IsException(iter)) return iter;
-      JSValue iter_obj = JS_Call(ctx, iter, arg, 0, NULL);
-      JS_FreeValue(ctx, iter);
-      if (JS_IsException(iter_obj)) return iter_obj;
-
-      JSValue result = JS_NewArray(ctx);
-      if (JS_IsException(result)) {
-        JS_FreeValue(ctx, iter_obj);
-        return result;
-      }
-
-      int64_t idx = 0;
-      while (1) {
-        JSValue next = JS_Call(ctx, JS_GetProperty(ctx, iter_obj, JS_ATOM_next), iter_obj, 0, NULL);
-        if (JS_IsException(next)) {
-          JS_FreeValue(ctx, iter_obj);
-          JS_FreeValue(ctx, result);
-          return JS_EXCEPTION;
-        }
-        JSValue done = JS_GetProperty(ctx, next, JS_ATOM_done);
-        if (JS_ToBool(ctx, done)) {
-          JS_FreeValue(ctx, done);
-          JS_FreeValue(ctx, next);
-          break;
-        }
-        JS_FreeValue(ctx, done);
-        JSValue value = JS_GetProperty(ctx, next, JS_ATOM_value);
-        JS_FreeValue(ctx, next);
-        JS_SetPropertyInt64(ctx, result, idx++, value);
-      }
-      JS_FreeValue(ctx, iter_obj);
-      return result;
-    }
-
     /* Return object keys */
     return JS_GetOwnPropertyNames2(ctx, arg,
                                    JS_GPN_ENUM_ONLY | JS_GPN_STRING_MASK,