Add Iterator.from (#555)

quickjs.c

@@ -153,7 +153,7 @@ enum {
     JS_CLASS_SET,               /* u.map_state */
     JS_CLASS_WEAKMAP,           /* u.map_state */
     JS_CLASS_WEAKSET,           /* u.map_state */
-    JS_CLASS_ITERATOR,          /* u.map_iterator_data */
+    JS_CLASS_ITERATOR,
     JS_CLASS_MAP_ITERATOR,      /* u.map_iterator_data */
     JS_CLASS_SET_ITERATOR,      /* u.map_iterator_data */
     JS_CLASS_ARRAY_ITERATOR,    /* u.array_iterator_data */
@@ -39770,7 +39770,53 @@ static JSValue js_iterator_constructor(JSContext *ctx, JSValue new_target,
 static JSValue js_iterator_from(JSContext *ctx, JSValue this_val,
                                 int argc, JSValue *argv)
 {
-    return JS_ThrowInternalError(ctx, "TODO implement Iterator.from");
+    JSValue obj, method, iter, temp;
+    int ret;
+
+    obj = argv[0];
+    if (JS_IsString(obj)) {
+        method = JS_GetProperty(ctx, obj, JS_ATOM_Symbol_iterator);
+        if (JS_IsException(method))
+            return JS_EXCEPTION;
+        return JS_CallFree(ctx, method, obj, 0, NULL);
+    }
+    if (!JS_IsObject(obj))
+        return JS_ThrowTypeError(ctx, "Iterator.from called on non-object");
+    ret = JS_OrdinaryIsInstanceOf(ctx, obj, ctx->iterator_ctor);
+    if (ret < 0)
+        return JS_EXCEPTION;
+    if (ret)
+        return js_dup(obj);
+    method = JS_GetProperty(ctx, obj, JS_ATOM_Symbol_iterator);
+    if (JS_IsException(method))
+        return JS_EXCEPTION;
+    if (JS_IsNull(method) || JS_IsUndefined(method)) {
+        method = JS_GetProperty(ctx, obj, JS_ATOM_next);
+        if (JS_IsException(method))
+            return JS_EXCEPTION;
+        // honestly kind of ghetto but avoids having to
+        // define a separate JS_CLASS_NON_GHETTO_ITERATOR
+        temp = method;
+        method = js_function_bind(ctx, method, 1, &obj);
+        JS_FreeValue(ctx, temp);
+        if (JS_IsException(method))
+            return JS_EXCEPTION;
+        iter = JS_NewObjectProtoClass(ctx, ctx->iterator_proto, JS_CLASS_ITERATOR);
+        if (JS_IsException(iter)) {
+            JS_FreeValue(ctx, method);
+            return JS_EXCEPTION;
+        }
+        if (JS_SetProperty(ctx, iter, JS_ATOM_next, method) < 0) {
+            JS_FreeValue(ctx, iter);
+            return JS_EXCEPTION;
+        }
+    } else {
+        iter = JS_GetIterator2(ctx, obj, method);
+        JS_FreeValue(ctx, method);
+        if (JS_IsException(iter))
+            return JS_EXCEPTION;
+    }
+    return iter;
 }
 
 static JSValue js_iterator_proto_drop(JSContext *ctx, JSValue this_val,

test262_errors.txt

@@ -18,24 +18,6 @@ test262/test/built-ins/AsyncFromSyncIteratorPrototype/throw/throw-undefined-retu
 test262/test/built-ins/AsyncFromSyncIteratorPrototype/throw/throw-undefined-return-not-object.js:72: strict mode: TypeError: $DONE() not called
 test262/test/built-ins/AsyncFromSyncIteratorPrototype/throw/throw-undefined-return-object.js:66: TypeError: $DONE() not called
 test262/test/built-ins/AsyncFromSyncIteratorPrototype/throw/throw-undefined-return-object.js:66: strict mode: TypeError: $DONE() not called
-test262/test/built-ins/Iterator/from/callable.js:11: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/callable.js:11: strict mode: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/get-next-method-only-once.js:38: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/get-next-method-only-once.js:38: strict mode: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/get-next-method-throws.js:17: Test262Error: Expected a Test262Error but got a InternalError
-test262/test/built-ins/Iterator/from/get-next-method-throws.js:17: strict mode: Test262Error: Expected a Test262Error but got a InternalError
-test262/test/built-ins/Iterator/from/iterable-primitives.js:33: Test262Error: Expected a TypeError but got a InternalError
-test262/test/built-ins/Iterator/from/iterable-primitives.js:33: strict mode: Test262Error: Expected a TypeError but got a InternalError
-test262/test/built-ins/Iterator/from/iterable-to-iterator-fallback.js:29: Test262Error: Expected a TypeError but got a InternalError
-test262/test/built-ins/Iterator/from/iterable-to-iterator-fallback.js:29: strict mode: Test262Error: Expected a TypeError but got a InternalError
-test262/test/built-ins/Iterator/from/primitives.js:14: Test262Error: Expected a TypeError but got a InternalError
-test262/test/built-ins/Iterator/from/primitives.js:14: strict mode: Test262Error: Expected a TypeError but got a InternalError
-test262/test/built-ins/Iterator/from/result-proto.js:19: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/result-proto.js:19: strict mode: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/supports-iterable.js:14: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/supports-iterable.js:14: strict mode: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/supports-iterator.js:29: InternalError: TODO implement Iterator.from
-test262/test/built-ins/Iterator/from/supports-iterator.js:29: strict mode: InternalError: TODO implement Iterator.from
 test262/test/built-ins/Iterator/prototype/Symbol.iterator/prop-desc.js:15: Test262Error: obj should have an own property Symbol(Symbol.iterator)
 test262/test/built-ins/Iterator/prototype/Symbol.iterator/prop-desc.js:15: strict mode: Test262Error: obj should have an own property Symbol(Symbol.iterator)
 test262/test/built-ins/Iterator/prototype/Symbol.toStringTag/prop-desc.js:11: TypeError: cannot read property 'get' of undefined