feat(esl-utils): extend attr decorator with inherit option to take …

…over the value of declared attribute

src/modules/esl-utils/decorators/attr.ts

@@ -1,6 +1,6 @@
 import {identity, resolveProperty} from '../misc/functions';
 import {parseString, toKebabCase} from '../misc/format';
-import {getAttr, setAttr} from '../dom/attr';
+import {getAttr, getClosestAttr, setAttr} from '../dom/attr';
 
 import type {PropertyProvider} from '../misc/functions';
 import type {ESLAttributeDecorator} from '../dom/attr';
@@ -15,6 +15,13 @@ type AttrDescriptor<T = string> = {
   name?: string;
   /** Create getter only */
   readonly?: boolean;
+  /** Find value to inherit across closest elements in DOM tree based on declared attribute name (in case of string format)
+   * or same attribute name of current element (boolean value).
+   * Example, attribute 'ignore' with configuration:
+   * inherit: 'alt-ignore' - searches ignore or data-ignore attr (in case of dataAttr: true) on this element or alt-ignore attribute on closest parent
+   * inherit: true - searches ignore or data-ignore attr (in case of dataAttr: true) on this element or on closest parent
+   */
+  inherit?: boolean | string;
   /** Use data-* attribute */
   dataAttr?: boolean;
   /** Default property value. Used if no attribute is present on the element. Empty string by default. Supports provider function. */
@@ -36,14 +43,14 @@ const buildAttrName =
 export const attr = <T = string>(config: AttrDescriptor<T> = {}): ESLAttributeDecorator => {
   return (target: ESLDomElementTarget, propName: string): any => {
     const attrName = buildAttrName(config.name || propName, !!config.dataAttr);
+    const closestAttrName = typeof config.inherit === 'string' ? config.inherit : attrName;
 
     function get(): T | null {
-      const val = getAttr(this, attrName);
-      if (val === null && 'defaultValue' in config) {
-        return resolveProperty(config.defaultValue, this) as T;
-      }
+      const val = config.inherit ? getClosestAttr(this, closestAttrName) || getAttr(this, attrName) : getAttr(this, attrName);
+      if (val === null && 'defaultValue' in config) return resolveProperty(config.defaultValue, this) as T;
       return (config.parser || parseString as AttrParser<any>)(val);
     }
+
     function set(value: T): void {
       setAttr(this, attrName, (config.serializer as AttrSerializer<any> || identity)(value));
     }

src/modules/esl-utils/dom/attr.ts

@@ -35,3 +35,10 @@ export function setAttr($el: ESLAttributeTarget, name: string, value: undefined
     $el.setAttribute(name, value === true ? '' : value);
   }
 }
+
+/** Gets attribute value from the closest element with group behavior settings */
+export function getClosestAttr($el: ESLAttributeTarget, attrName: string): string | null {
+  if (!($el = resolveDomTarget($el))) return null;
+  const $closest = $el.closest(`[${attrName}]`);
+  return $closest ? $closest.getAttribute(attrName) : null;
+}