diff --git a/quickjs.c b/quickjs.c
index e30d393..8a11cf3 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -9153,14 +9153,15 @@ static inline int add_fast_array_element(JSContext *ctx, JSObject *p,
     return TRUE;
 }
 
-/* Allocate a new fast array. Its 'length' property is set to zero. It
-   maximum size is 2^31-1 elements. For convenience, 'len' is a 64 bit
-   integer. WARNING: the content of the array is not initialized. */
+/* Allocate a new fast array initialized to JS_UNDEFINED. Its maximum
+   size is 2^31-1 elements. For convenience, 'len' is a 64 bit
+   integer. */
 static JSValue js_allocate_fast_array(JSContext *ctx, int64_t len)
 {
     JSValue arr;
     JSObject *p;
-
+    int i;
+    
     if (len > INT32_MAX)
         return JS_ThrowRangeError(ctx, "invalid array length");
     arr = JS_NewArray(ctx);
@@ -9173,6 +9174,10 @@ static JSValue js_allocate_fast_array(JSContext *ctx, int64_t len)
             return JS_EXCEPTION;
         }
         p->u.array.count = len;
+        for(i = 0; i < len; i++) 
+            p->u.array.u.values[i] = JS_UNDEFINED;
+        /* update the 'length' field */
+        set_value(ctx, &p->prop[0].u.value, JS_NewInt32(ctx, len));
     }
     return arr;
 }
@@ -41395,21 +41400,14 @@ static JSValue js_array_with(JSContext *ctx, JSValueConst this_val,
     } else {
         for (; i < idx; i++, pval++)
             if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval))
-                goto fill_and_fail;
+                goto exception;
         *pval = JS_DupValue(ctx, argv[1]);
         for (i++, pval++; i < len; i++, pval++) {
-            if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval)) {
-            fill_and_fail:
-                for (; i < len; i++, pval++)
-                    *pval = JS_UNDEFINED;
+            if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval))
                 goto exception;
-            }
         }
     }
 
-    if (JS_SetProperty(ctx, arr, JS_ATOM_length, JS_NewInt64(ctx, len)) < 0)
-        goto exception;
-
     ret = arr;
     arr = JS_UNDEFINED;
 
@@ -42293,17 +42291,10 @@ static JSValue js_array_toReversed(JSContext *ctx, JSValueConst this_val,
         } else {
             // Query order is observable; test262 expects descending order.
             for (; i >= 0; i--, pval++) {
-                if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval)) {
-                    // Exception; initialize remaining elements.
-                    for (; i >= 0; i--, pval++)
-                        *pval = JS_UNDEFINED;
+                if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval))
                     goto exception;
-                }
             }
         }
-
-        if (JS_SetProperty(ctx, arr, JS_ATOM_length, JS_NewInt64(ctx, len)) < 0)
-            goto exception;
     }
 
     ret = arr;
@@ -42492,17 +42483,11 @@ static JSValue js_array_toSpliced(JSContext *ctx, JSValueConst this_val,
 
     assert(pval == last);
 
-    if (JS_SetProperty(ctx, arr, JS_ATOM_length, JS_NewInt64(ctx, newlen)) < 0)
-        goto exception;
-
 done:
     ret = arr;
     arr = JS_UNDEFINED;
 
 exception:
-    while (pval != last)
-        *pval++ = JS_UNDEFINED;
-
     JS_FreeValue(ctx, arr);
     JS_FreeValue(ctx, obj);
     return ret;
@@ -42847,16 +42832,10 @@ static JSValue js_array_toSorted(JSContext *ctx, JSValueConst this_val,
                 *pval = JS_DupValue(ctx, arrp[i]);
         } else {
             for (; i < len; i++, pval++) {
-                if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval)) {
-                    for (; i < len; i++, pval++)
-                        *pval = JS_UNDEFINED;
+                if (-1 == JS_TryGetPropertyInt64(ctx, obj, i, pval))
                     goto exception;
-                }
             }
         }
-
-        if (JS_SetProperty(ctx, arr, JS_ATOM_length, JS_NewInt64(ctx, len)) < 0)
-            goto exception;
     }
 
     ret = js_array_sort(ctx, arr, argc, argv);