Improve set-cookie scriptlet

Allow negative integer as valid value.

Related issue:
#3927

Additionally, move cookie-related scriptlets/helpers into its own
source code file.

Author: gorhill

assets/resources/set-attr.js renamed to assets/resources/attribute.js

@@ -198,4 +198,108 @@ trustedSetAttr.details = {
     world: 'ISOLATED',
 };
 
+/**
+ * @scriptlet remove-attr
+ * 
+ * @description
+ * Remove one or more attributes from a set of elements.
+ * 
+ * @param attribute
+ * The name of the attribute(s) to remove. This can be a list of space-
+ * separated attribute names.
+ * 
+ * @param [selector]
+ * Optional. A CSS selector for the elements to target. Default to
+ * `[attribute]`, or `[attribute1],[attribute2],...` if more than one
+ * attribute name is specified.
+ * 
+ * @param [behavior]
+ * Optional. Space-separated tokens which modify the default behavior.
+ * - `asap`: Try to remove the attribute as soon as possible. Default behavior
+ *   is to remove the attribute(s) asynchronously. 
+ * - `stay`: Keep trying to remove the specified attribute(s) on DOM mutations.
+ * */
+
+export function removeAttr(
+    rawToken = '',
+    rawSelector = '',
+    behavior = ''
+) {
+    if ( typeof rawToken !== 'string' ) { return; }
+    if ( rawToken === '' ) { return; }
+    const safe = safeSelf();
+    const logPrefix = safe.makeLogPrefix('remove-attr', rawToken, rawSelector, behavior);
+    const tokens = rawToken.split(/\s*\|\s*/);
+    const selector = tokens
+        .map(a => `${rawSelector}[${CSS.escape(a)}]`)
+        .join(',');
+    if ( safe.logLevel > 1 ) {
+        safe.uboLog(logPrefix, `Target selector:\n\t${selector}`);
+    }
+    const asap = /\basap\b/.test(behavior);
+    let timerId;
+    const rmattrAsync = ( ) => {
+        if ( timerId !== undefined ) { return; }
+        timerId = safe.onIdle(( ) => {
+            timerId = undefined;
+            rmattr();
+        }, { timeout: 17 });
+    };
+    const rmattr = ( ) => {
+        if ( timerId !== undefined ) {
+            safe.offIdle(timerId);
+            timerId = undefined;
+        }
+        try {
+            const nodes = document.querySelectorAll(selector);
+            for ( const node of nodes ) {
+                for ( const attr of tokens ) {
+                    if ( node.hasAttribute(attr) === false ) { continue; }
+                    node.removeAttribute(attr);
+                    safe.uboLog(logPrefix, `Removed attribute '${attr}'`);
+                }
+            }
+        } catch(ex) {
+        }
+    };
+    const mutationHandler = mutations => {
+        if ( timerId !== undefined ) { return; }
+        let skip = true;
+        for ( let i = 0; i < mutations.length && skip; i++ ) {
+            const { type, addedNodes, removedNodes } = mutations[i];
+            if ( type === 'attributes' ) { skip = false; }
+            for ( let j = 0; j < addedNodes.length && skip; j++ ) {
+                if ( addedNodes[j].nodeType === 1 ) { skip = false; break; }
+            }
+            for ( let j = 0; j < removedNodes.length && skip; j++ ) {
+                if ( removedNodes[j].nodeType === 1 ) { skip = false; break; }
+            }
+        }
+        if ( skip ) { return; }
+        asap ? rmattr() : rmattrAsync();
+    };
+    const start = ( ) => {
+        rmattr();
+        if ( /\bstay\b/.test(behavior) === false ) { return; }
+        const observer = new MutationObserver(mutationHandler);
+        observer.observe(document, {
+            attributes: true,
+            attributeFilter: tokens,
+            childList: true,
+            subtree: true,
+        });
+    };
+    runAt(( ) => { start(); }, behavior.split(/\s+/));
+}
+removeAttr.details = {
+    name: 'remove-attr.js',
+    aliases: [
+        'ra.js',
+    ],
+    dependencies: [
+        runAt,
+        safeSelf,
+    ],
+};
+
 /******************************************************************************/