3 files changed, 61 insertions, 0 deletions
diff --git a/src/shared/modify-dom.ts b/src/shared/modify-dom.ts
new file mode 100644
index 0000000..0832d5b
--- /dev/null
+++ b/src/shared/modify-dom.ts
@@ -0,0 +1,41 @@
+import { observeDOM } from "/shared/observe-dom";
+
+type DOMReplacements = {
+	innerHTML?: string;
+	[key: string]: string | undefined | null;
+};
+
+type DOMModificaitonRule = readonly [string, DOMReplacements];
+
+export const modifyDOM = (modificationRules: (DOMModificaitonRule | null)[]) => {
+	let count = 0;
+
+	observeDOM(() => {
+		for (let i = 0; i < modificationRules.length; i++) {
+			if (modificationRules[i]) {
+				const element = document.querySelector(modificationRules[i]![0]) as HTMLElement | null;
+				if (element) {
+					const attributes = modificationRules[i]![1] as DOMReplacements;
+					if (attributes.innerHTML) {
+						element.innerHTML = attributes.innerHTML as string;
+					}
+					delete attributes.innerHTML;
+					for (const attribute in attributes) {
+						if (attributes[attribute] === null) {
+							element.removeAttribute(attribute);
+						} else {
+							element.setAttribute(attribute, attributes[attribute] as string);
+						}
+					}
+					modificationRules[i] = null;
+					count++;
+					if (count >= modificationRules.length) {
+						return true;
+					}
+				}
+			}
+		}
+
+		return false;
+	});
+};
diff --git a/src/shared/observe-dom.ts b/src/shared/observe-dom.ts
new file mode 100644
index 0000000..4a447a0
--- /dev/null
+++ b/src/shared/observe-dom.ts
@@ -0,0 +1,12 @@
+export const observeDOM = (callback: () => boolean) => {
+	const observer = new MutationObserver(() => {
+		if (callback()) {
+			observer.disconnect();
+		}
+	});
+
+	observer.observe(document, {
+		childList: true,
+		subtree: true
+	});
+};
diff --git a/src/shared/styling.ts b/src/shared/styling.ts
new file mode 100644
index 0000000..0e527d9
--- /dev/null
+++ b/src/shared/styling.ts
@@ -0,0 +1,8 @@
+export const styles = (selector: string, styles: { [key: string]: string }) => {
+	const  elements = Array.from(document.querySelectorAll(selector)) as HTMLElement[];
+	for (const element of elements) {
+		for (const styleType in styles) {
+			element.style[styleType as any] = styles[styleType];
+		}
+	}
+};