stash lookup

Author: Rich-Harris

packages/svelte/src/internal/client/dom/elements/attributes.js

@@ -20,6 +20,9 @@ import { NAMESPACE_HTML } from '../../../../constants.js';
 export const CLASS = Symbol('class');
 export const STYLE = Symbol('style');
 
+const IS_CUSTOM_ELEMENT = Symbol('is custom element');
+const IS_HTML = Symbol('is html');
+
 /**
  * The value/checked attribute in the template actually corresponds to the defaultValue property, so we need
  * to remove it upon hydration to avoid a bug when someone resets the form value.
@@ -64,8 +67,7 @@ export function remove_input_defaults(input) {
  * @param {any} value
  */
 export function set_value(element, value) {
-	// @ts-expect-error
-	var attributes = (element.__attributes ??= {});
+	var attributes = get_attributes(element);
 
 	if (
 		attributes.value ===
@@ -88,8 +90,7 @@ export function set_value(element, value) {
  * @param {boolean} checked
  */
 export function set_checked(element, checked) {
-	// @ts-expect-error
-	var attributes = (element.__attributes ??= {});
+	var attributes = get_attributes(element);
 
 	if (
 		attributes.checked ===
@@ -152,8 +153,7 @@ export function set_default_value(element, value) {
  * @param {boolean} [skip_warning]
  */
 export function set_attribute(element, attribute, value, skip_warning) {
-	// @ts-expect-error
-	var attributes = (element.__attributes ??= {});
+	var attributes = get_attributes(element);
 
 	if (hydrating) {
 		attributes[attribute] = element.getAttribute(attribute);
@@ -266,8 +266,10 @@ export function set_custom_element_data(node, prop, value) {
  * @returns {Record<string, any>}
  */
 export function set_attributes(element, prev, next, css_hash, skip_warning = false) {
-	var is_custom_element = element.nodeName.includes('-');
-	var preserve_attribute_case = is_custom_element || element.namespaceURI !== NAMESPACE_HTML;
+	var attributes = get_attributes(element);
+
+	var is_custom_element = attributes[IS_CUSTOM_ELEMENT];
+	var preserve_attribute_case = !attributes[IS_HTML];
 
 	// If we're hydrating but the custom element is from Svelte, and it already scaffolded,
 	// then it might run block logic in hydration mode, which we have to prevent.
@@ -293,9 +295,6 @@ export function set_attributes(element, prev, next, css_hash, skip_warning = fal
 
 	var setters = get_setters(element);
 
-	// @ts-expect-error
-	var attributes = /** @type {Record<string, unknown>} **/ (element.__attributes ??= {});
-
 	// since key is captured we use const
 	for (const key in next) {
 		// let instead of var because referenced in a closure
@@ -442,6 +441,20 @@ export function set_attributes(element, prev, next, css_hash, skip_warning = fal
 	return current;
 }
 
+/**
+ *
+ * @param {Element} element
+ */
+function get_attributes(element) {
+	return /** @type {Record<string | symbol, unknown>} **/ (
+		// @ts-expect-error
+		element.__attributes ??= {
+			[IS_CUSTOM_ELEMENT]: element.nodeName.includes('-'),
+			[IS_HTML]: element.namespaceURI === NAMESPACE_HTML
+		}
+	);
+}
+
 /** @type {Map<string, string[]>} */
 var setters_cache = new Map();