First commits be like

sunpy/node/nodes/basenode.js

@@ -0,0 +1,5 @@
+export class BaseNode {
+    constructor(node) {
+        this.node = node;
+    }
+}

sunpy/node/nodes/propertynode.js

@@ -0,0 +1,22 @@
+import { SwapNode } from "./swapnode.js";
+import { PropertyReader } from "../propertyreader.js";
+
+export class PropertyNode extends SwapNode {
+    constructor(node, swapNode, propertyReader) {
+        super(node, swapNode);
+
+        if (!(propertyReader instanceof PropertyReader))
+            throw TypeError("propertyReader must be an instance of PropertyReader");
+
+        this.propertyReader = propertyReader;
+
+        super.replaceNodes();
+    }
+
+    /**
+     * @override
+     */
+    linker(node, swapNode) {
+        this.properties = this.propertyReader.read(node.innerText);
+    }
+}

sunpy/node/nodes/swapnode.js

@@ -0,0 +1,35 @@
+import { BaseNode } from "./basenode.js";
+
+export class SwapNode extends BaseNode {
+    constructor(node, swapNode) {
+        super(node);
+        
+        if (!(swapNode instanceof Node))
+            throw TypeError("swapNode must be instance of Node");
+
+        this.swapNode = swapNode;
+
+        this.hasReplaceNodes = false;
+    }
+
+    replaceNodes() {
+        if (this.hasReplaceNodes)
+            return false;
+
+        this.linker(this.node, this.swapNode);
+
+        this.node.parentNode.replaceChild(this.swapNode, this.node);
+        this.node = this.swapNode;
+
+        delete this.swapNode;
+
+        return this.hasReplaceNodes = true;
+    }
+
+    /**
+     * Override this to have access to the script tag that gets converted to the new node inplace
+     * @param {Node} node Node of the original script tag
+     * @param {Node} swapNode Node of the new element that replaces the script tag inline
+     */
+    linker(node, swapNode) {}
+}