Implement Error causes (#103)

Author: littledivy

quickjs-atom.h

@@ -82,6 +82,7 @@ DEF(length, "length")
 DEF(fileName, "fileName")
 DEF(lineNumber, "lineNumber")
 DEF(message, "message")
+DEF(cause, "cause")
 DEF(errors, "errors")
 DEF(stack, "stack")
 DEF(name, "name")

quickjs.c

@@ -35282,8 +35282,10 @@ static JSValue iterator_to_array(JSContext *ctx, JSValueConst items)
 static JSValue js_error_constructor(JSContext *ctx, JSValueConst new_target,
                                     int argc, JSValueConst *argv, int magic)
 {
-    JSValue obj, msg, proto;
+    JSValue obj, msg, proto, cause;
     JSValueConst message;
+    int opts;
+    BOOL present;
 
     if (JS_IsUndefined(new_target))
         new_target = JS_GetActiveFunction(ctx);
@@ -35311,8 +35313,10 @@ static JSValue js_error_constructor(JSContext *ctx, JSValueConst new_target,
         return obj;
     if (magic == JS_AGGREGATE_ERROR) {
         message = argv[1];
+        opts = 2;
     } else {
         message = argv[0];
+        opts = 1;
     }
 
     if (!JS_IsUndefined(message)) {
@@ -35323,6 +35327,19 @@ static JSValue js_error_constructor(JSContext *ctx, JSValueConst new_target,
                                JS_PROP_WRITABLE | JS_PROP_CONFIGURABLE);
     }
 
+    if (argc > opts && JS_VALUE_GET_TAG(argv[opts]) == JS_TAG_OBJECT) {
+        present = JS_HasProperty(ctx, argv[opts], JS_ATOM_cause);
+        if (unlikely(present < 0))
+            goto exception;
+        if (present) {
+            cause = JS_GetProperty(ctx, argv[opts], JS_ATOM_cause);
+            if (unlikely(JS_IsException(cause)))
+                goto exception;
+            JS_DefinePropertyValue(ctx, obj, JS_ATOM_cause, cause,
+                                   JS_PROP_WRITABLE | JS_PROP_CONFIGURABLE);
+        }
+    }
+
     if (magic == JS_AGGREGATE_ERROR) {
         JSValue error_list = iterator_to_array(ctx, argv[0]);
         if (JS_IsException(error_list))

test262.conf

@@ -102,7 +102,7 @@ default-parameters
 destructuring-assignment
 destructuring-binding
 dynamic-import
-error-cause=skip
+error-cause
 exponentiation
 export-star-as-namespace-from-module
 FinalizationGroup=skip