add special [attribute-name] param value

src/helpers/attribute-utils.ts

@@ -1,28 +1,53 @@
-import { hit } from './hit';
 import { logMessage } from './log-message';
+import { hit } from './hit';
+
+/**
+ * Sets attribute with given value to given element.
+ *
+ * @param elem
+ * @param attribute
+ * @param value
+ * @returns
+ */
+const defaultAttributeSetter = (
+    elem: Element,
+    attribute: string,
+    value: string,
+): void => elem.setAttribute(attribute, value);
 
 /**
  * Sets attribute with given value to all elements matching given selector
  *
- * @param source source object
+ * @param source source
  * @param selector CSS selector
- * @param attr attribute name to set
+ * @param attribute attribute name to set
  * @param value attribute value to set
+ * @param attributeSetter function to apply to each element,
+ * defaults to native .setAttribute
  */
-export const setAttributeToSelection = (
+export const setAttributeBySelector = (
     source: Source,
     selector: string,
-    attr: string,
+    attribute: string,
     value: string,
+    attributeSetter = defaultAttributeSetter,
 ): void => {
+    let elements;
+    try {
+        elements = document.querySelectorAll(selector);
+    } catch {
+        logMessage(source, `Failed to find elements matching selector "${selector}"`);
+        return;
+    }
+
+    if (!elements || elements.length === 0) {
+        return;
+    }
+
     try {
-        const nodes = document.querySelectorAll(selector);
-        if (nodes.length === 0) {
-            return;
-        }
-        nodes.forEach((node) => node.setAttribute(attr, value));
+        elements.forEach((elem) => attributeSetter(elem, attribute, value));
         hit(source);
     } catch {
-        logMessage(source, `Failed to set attribute "${attr}" to "${value}" on "${selector}"`);
+        logMessage(source, `Failed to set [${attribute}="${value}"] to each of selected elements.`);
     }
 };

src/scriptlets/set-attr.js

@@ -1,5 +1,5 @@
 import {
-    setAttributeToSelection,
+    setAttributeBySelector,
     observeDOMChanges,
     nativeIsNaN,
     // following helpers should be imported and injected
@@ -32,6 +32,7 @@ import {
  *     - `''` — empty string
  *     - positive decimal integer `<= 32767`
  *     - `true` / `false` in any case variation
+ *     - `[attribute-name]` copy the value from attribute `attribute-name` on the same element.
  *
  * ### Examples
  *
@@ -97,6 +98,20 @@ import {
  *     <a class="class" test-attribute="fAlse">Some text</div>
  *     ```
  *
+ * 1. Copy attribute value from the target element
+ *
+ *     ```adblock
+ *     example.org#%#//scriptlet('set-attr', 'iframe[data-cur]', 'href', '[data-cur]')
+ *     ```
+ *
+ *     ```html
+ *     <!-- before -->
+ *     <iframe data-cur="good-url.com" href="bad-url.org"></iframe>
+ *
+ *     <!-- after -->
+ *     <iframe data-cur="good-url.com" href="good-url.com"></iframe>
+ *     ```
+ *
  * @added v1.5.0.
  */
 /* eslint-enable max-len */
@@ -107,17 +122,33 @@ export function setAttr(source, selector, attr, value = '') {
 
     const allowedValues = ['true', 'false'];
 
-    // Drop strings that cant be parsed into number, negative numbers and numbers below 32767
-    if (value.length !== 0
+    const shouldCopyValue = value.startsWith('[') && value.endsWith(']');
+    const isIllegalValue = value.length !== 0
         && (nativeIsNaN(parseInt(value, 10))
             || parseInt(value, 10) < 0
             || parseInt(value, 10) > 32767)
-        && !allowedValues.includes(value.toLowerCase())) {
+        && !allowedValues.includes(value.toLowerCase());
+
+    if (!shouldCopyValue && isIllegalValue) {
+        logMessage(source, 'Illegal attribute value provided');
         return;
     }
 
-    setAttributeToSelection(source, selector, attr, value);
-    observeDOMChanges(() => setAttributeToSelection(source, selector, attr, value), true);
+    /**
+     * Defining value extraction logic here allows us to remove
+     * excessive `shouldCopyValue` checks in observer callback.
+     * Setting plain value is a default behavior.
+     */
+    let attributeHandler;
+    if (shouldCopyValue) {
+        attributeHandler = (elem, attr, value) => {
+            const valueToCopy = elem.getAttribute(value.slice(1, -1));
+            elem.setAttribute(attr, valueToCopy);
+        };
+    }
+
+    setAttributeBySelector(source, selector, attr, value, attributeHandler);
+    observeDOMChanges(() => setAttributeBySelector(source, selector, attr, value, attributeHandler), true);
 }
 
 setAttr.names = [
@@ -129,7 +160,7 @@ setAttr.names = [
 ];
 
 setAttr.injections = [
-    setAttributeToSelection,
+    setAttributeBySelector,
     observeDOMChanges,
     nativeIsNaN,
     // following helpers should be imported and injected

src/scriptlets/trusted-set-attr.js

@@ -1,5 +1,5 @@
 import {
-    setAttributeToSelection,
+    setAttributeBySelector,
     observeDOMChanges,
     nativeIsNaN,
     // following helpers should be imported and injected
@@ -99,8 +99,8 @@ export function trustedSetAttr(source, selector, attr, value = '') {
         return;
     }
 
-    setAttributeToSelection(source, selector, attr, value);
-    observeDOMChanges(() => setAttributeToSelection(source, selector, attr, value), true);
+    setAttributeBySelector(source, selector, attr, value);
+    observeDOMChanges(() => setAttributeBySelector(source, selector, attr, value), true);
 }
 
 trustedSetAttr.names = [
@@ -109,7 +109,7 @@ trustedSetAttr.names = [
 ];
 
 trustedSetAttr.injections = [
-    setAttributeToSelection,
+    setAttributeBySelector,
     observeDOMChanges,
     nativeIsNaN,
     // following helpers should be imported and injected