|  | @@ -0,0 +1,141 @@
 | 
	
		
			
				|  |  | +//==========================================================
 | 
	
		
			
				|  |  | +// head-support.js
 | 
	
		
			
				|  |  | +//
 | 
	
		
			
				|  |  | +// An extension to htmx 1.0 to add head tag merging.
 | 
	
		
			
				|  |  | +//==========================================================
 | 
	
		
			
				|  |  | +(function(){
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +    var api = null;
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +    function log() {
 | 
	
		
			
				|  |  | +        //console.log(arguments);
 | 
	
		
			
				|  |  | +    }
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +    function mergeHead(newContent, defaultMergeStrategy) {
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +        if (newContent && newContent.indexOf('<head') > -1) {
 | 
	
		
			
				|  |  | +            const htmlDoc = document.createElement("html");
 | 
	
		
			
				|  |  | +            // remove svgs to avoid conflicts
 | 
	
		
			
				|  |  | +            var contentWithSvgsRemoved = newContent.replace(/<svg(\s[^>]*>|>)([\s\S]*?)<\/svg>/gim, '');
 | 
	
		
			
				|  |  | +            // extract head tag
 | 
	
		
			
				|  |  | +            var headTag = contentWithSvgsRemoved.match(/(<head(\s[^>]*>|>)([\s\S]*?)<\/head>)/im);
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +            // if the  head tag exists...
 | 
	
		
			
				|  |  | +            if (headTag) {
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                var added = []
 | 
	
		
			
				|  |  | +                var removed = []
 | 
	
		
			
				|  |  | +                var preserved = []
 | 
	
		
			
				|  |  | +                var nodesToAppend = []
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                htmlDoc.innerHTML = headTag;
 | 
	
		
			
				|  |  | +                var newHeadTag = htmlDoc.querySelector("head");
 | 
	
		
			
				|  |  | +                var currentHead = document.head;
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                if (newHeadTag == null) {
 | 
	
		
			
				|  |  | +                    return;
 | 
	
		
			
				|  |  | +                } else {
 | 
	
		
			
				|  |  | +                    // put all new head elements into a Map, by their outerHTML
 | 
	
		
			
				|  |  | +                    var srcToNewHeadNodes = new Map();
 | 
	
		
			
				|  |  | +                    for (const newHeadChild of newHeadTag.children) {
 | 
	
		
			
				|  |  | +                        srcToNewHeadNodes.set(newHeadChild.outerHTML, newHeadChild);
 | 
	
		
			
				|  |  | +                    }
 | 
	
		
			
				|  |  | +                }
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                // determine merge strategy
 | 
	
		
			
				|  |  | +                var mergeStrategy = api.getAttributeValue(newHeadTag, "hx-head") || defaultMergeStrategy;
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                // get the current head
 | 
	
		
			
				|  |  | +                for (const currentHeadElt of currentHead.children) {
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                    // If the current head element is in the map
 | 
	
		
			
				|  |  | +                    var inNewContent = srcToNewHeadNodes.has(currentHeadElt.outerHTML);
 | 
	
		
			
				|  |  | +                    var isReAppended = currentHeadElt.getAttribute("hx-head") === "re-eval";
 | 
	
		
			
				|  |  | +                    var isPreserved = api.getAttributeValue(currentHeadElt, "hx-preserve") === "true";
 | 
	
		
			
				|  |  | +                    if (inNewContent || isPreserved) {
 | 
	
		
			
				|  |  | +                        if (isReAppended) {
 | 
	
		
			
				|  |  | +                            // remove the current version and let the new version replace it and re-execute
 | 
	
		
			
				|  |  | +                            removed.push(currentHeadElt);
 | 
	
		
			
				|  |  | +                        } else {
 | 
	
		
			
				|  |  | +                            // this element already exists and should not be re-appended, so remove it from
 | 
	
		
			
				|  |  | +                            // the new content map, preserving it in the DOM
 | 
	
		
			
				|  |  | +                            srcToNewHeadNodes.delete(currentHeadElt.outerHTML);
 | 
	
		
			
				|  |  | +                            preserved.push(currentHeadElt);
 | 
	
		
			
				|  |  | +                        }
 | 
	
		
			
				|  |  | +                    } else {
 | 
	
		
			
				|  |  | +                        if (mergeStrategy === "append") {
 | 
	
		
			
				|  |  | +                            // we are appending and this existing element is not new content
 | 
	
		
			
				|  |  | +                            // so if and only if it is marked for re-append do we do anything
 | 
	
		
			
				|  |  | +                            if (isReAppended) {
 | 
	
		
			
				|  |  | +                                removed.push(currentHeadElt);
 | 
	
		
			
				|  |  | +                                nodesToAppend.push(currentHeadElt);
 | 
	
		
			
				|  |  | +                            }
 | 
	
		
			
				|  |  | +                        } else {
 | 
	
		
			
				|  |  | +                            // if this is a merge, we remove this content since it is not in the new head
 | 
	
		
			
				|  |  | +                            if (api.triggerEvent(document.body, "htmx:removingHeadElement", {headElement: currentHeadElt}) !== false) {
 | 
	
		
			
				|  |  | +                                removed.push(currentHeadElt);
 | 
	
		
			
				|  |  | +                            }
 | 
	
		
			
				|  |  | +                        }
 | 
	
		
			
				|  |  | +                    }
 | 
	
		
			
				|  |  | +                }
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                // Push the tremaining new head elements in the Map into the
 | 
	
		
			
				|  |  | +                // nodes to append to the head tag
 | 
	
		
			
				|  |  | +                nodesToAppend.push(...srcToNewHeadNodes.values());
 | 
	
		
			
				|  |  | +                log("to append: ", nodesToAppend);
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                for (const newNode of nodesToAppend) {
 | 
	
		
			
				|  |  | +                    log("adding: ", newNode);
 | 
	
		
			
				|  |  | +                    var newElt = document.createRange().createContextualFragment(newNode.outerHTML);
 | 
	
		
			
				|  |  | +                    log(newElt);
 | 
	
		
			
				|  |  | +                    if (api.triggerEvent(document.body, "htmx:addingHeadElement", {headElement: newElt}) !== false) {
 | 
	
		
			
				|  |  | +                        currentHead.appendChild(newElt);
 | 
	
		
			
				|  |  | +                        added.push(newElt);
 | 
	
		
			
				|  |  | +                    }
 | 
	
		
			
				|  |  | +                }
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                // remove all removed elements, after we have appended the new elements to avoid
 | 
	
		
			
				|  |  | +                // additional network requests for things like style sheets
 | 
	
		
			
				|  |  | +                for (const removedElement of removed) {
 | 
	
		
			
				|  |  | +                    if (api.triggerEvent(document.body, "htmx:removingHeadElement", {headElement: removedElement}) !== false) {
 | 
	
		
			
				|  |  | +                        currentHead.removeChild(removedElement);
 | 
	
		
			
				|  |  | +                    }
 | 
	
		
			
				|  |  | +                }
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +                api.triggerEvent(document.body, "htmx:afterHeadMerge", {added: added, kept: preserved, removed: removed});
 | 
	
		
			
				|  |  | +            }
 | 
	
		
			
				|  |  | +        }
 | 
	
		
			
				|  |  | +    }
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +    htmx.defineExtension("head-support", {
 | 
	
		
			
				|  |  | +        init: function(apiRef) {
 | 
	
		
			
				|  |  | +            // store a reference to the internal API.
 | 
	
		
			
				|  |  | +            api = apiRef;
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +            htmx.on('htmx:afterSwap', function(evt){
 | 
	
		
			
				|  |  | +                var serverResponse = evt.detail.xhr.response;
 | 
	
		
			
				|  |  | +                if (api.triggerEvent(document.body, "htmx:beforeHeadMerge", evt.detail)) {
 | 
	
		
			
				|  |  | +                    mergeHead(serverResponse, evt.detail.boosted ? "merge" : "append");
 | 
	
		
			
				|  |  | +                }
 | 
	
		
			
				|  |  | +            })
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +            htmx.on('htmx:historyRestore', function(evt){
 | 
	
		
			
				|  |  | +                if (api.triggerEvent(document.body, "htmx:beforeHeadMerge", evt.detail)) {
 | 
	
		
			
				|  |  | +                    if (evt.detail.cacheMiss) {
 | 
	
		
			
				|  |  | +                        mergeHead(evt.detail.serverResponse, "merge");
 | 
	
		
			
				|  |  | +                    } else {
 | 
	
		
			
				|  |  | +                        mergeHead(evt.detail.item.head, "merge");
 | 
	
		
			
				|  |  | +                    }
 | 
	
		
			
				|  |  | +                }
 | 
	
		
			
				|  |  | +            })
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +            htmx.on('htmx:historyItemCreated', function(evt){
 | 
	
		
			
				|  |  | +                var historyItem = evt.detail.item;
 | 
	
		
			
				|  |  | +                historyItem.head = document.head.outerHTML;
 | 
	
		
			
				|  |  | +            })
 | 
	
		
			
				|  |  | +        }
 | 
	
		
			
				|  |  | +    });
 | 
	
		
			
				|  |  | +
 | 
	
		
			
				|  |  | +})()
 |