diff --git a/.vscode/settings.json b/.vscode/settings.json
index 1295ee63..cd3023f6 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,3 +1,4 @@
 {
-	"editor.formatOnSave": true
+	"editor.formatOnSave": true,
+	"cSpell.words": ["pako", "Serde", "serdes"]
 }
diff --git a/src/lib/components/actions.svelte b/src/lib/components/actions.svelte
index 4b527d85..b3c411fa 100644
--- a/src/lib/components/actions.svelte
+++ b/src/lib/components/actions.svelte
@@ -18,7 +18,7 @@
 		}
 		const svgString = svg.outerHTML
 			.replaceAll('<br>', '<br/>')
-			.replaceAll(/<img([^>]*)>/g, (m, g) => `<img ${g} />`);
+			.replaceAll(/<img([^>]*)>/g, (m, g: string) => `<img ${g} />`);
 		return toBase64(svgString);
 	};
 
@@ -79,7 +79,7 @@
 			canvas.toBlob((blob) => {
 				try {
 					// @ts-ignore: https://github.com/microsoft/TypeScript-DOM-lib-generator/pull/1004/files
-					navigator.clipboard.write([
+					void navigator.clipboard.write([
 						/* eslint-disable no-undef */
 						// @ts-ignore: https://github.com/microsoft/TypeScript/issues/43821
 						new ClipboardItem({
diff --git a/src/lib/util/env.ts b/src/lib/util/env.ts
index f5e22f30..128761f2 100644
--- a/src/lib/util/env.ts
+++ b/src/lib/util/env.ts
@@ -1,2 +1,4 @@
-export const rendererUrl = import.meta.env.MERMAID_RENDERER_URL ?? 'https://mermaid.ink';
-export const krokiRendererUrl = import.meta.env.MERMAID_KROKI_RENDERER_URL ?? 'https://kroki.io';
+export const rendererUrl: string =
+	(import.meta.env.MERMAID_RENDERER_URL as string) ?? 'https://mermaid.ink';
+export const krokiRendererUrl: string =
+	(import.meta.env.MERMAID_KROKI_RENDERER_URL as string) ?? 'https://kroki.io';
diff --git a/src/lib/util/serde.ts b/src/lib/util/serde.ts
index 7f56ab25..1f7540fc 100644
--- a/src/lib/util/serde.ts
+++ b/src/lib/util/serde.ts
@@ -7,11 +7,6 @@ interface Serde {
 	deserialize: (state: string) => string;
 }
 
-enum SerdeType {
-	Base64 = 'base64',
-	Pako = 'pako'
-}
-
 const base64Serde: Serde = {
 	serialize: (state: string): string => {
 		return toBase64(state, true);
@@ -32,26 +27,35 @@ export const pakoSerde: Serde = {
 		return inflate(data, { to: 'string' });
 	}
 };
-const serdes: Map<string, Serde> = new Map([
-	[SerdeType.Base64, base64Serde],
-	[SerdeType.Pako, pakoSerde]
-]);
+
+const serdes: { [key: string]: Serde } = {
+	base64: base64Serde,
+	pako: pakoSerde
+};
+
+type SerdeType = keyof typeof serdes;
 
 export const serializeState = (state: State): string => {
 	const json = JSON.stringify(state);
-	const defaultSerde = SerdeType.Pako;
-	const serialized = serdes.get(defaultSerde).serialize(json);
+	const defaultSerde: SerdeType = 'pako';
+	const serialized = serdes[defaultSerde].serialize(json);
 	return `${defaultSerde}:${serialized}`;
 };
 
 export const deserializeState = (state: string): State => {
-	let type: string, serialized: string;
+	let type: SerdeType, serialized: string;
 	if (state.includes(':')) {
-		[type, serialized] = state.split(':');
+		let tempType: string;
+		[tempType, serialized] = state.split(':');
+		if (tempType in serdes) {
+			type = tempType;
+		} else {
+			throw new Error(`Unknown serde type: ${tempType}`);
+		}
 	} else {
-		type = SerdeType.Base64;
+		type = 'base64';
 		serialized = state;
 	}
-	const json = serdes.get(type).deserialize(serialized);
+	const json = serdes[type].deserialize(serialized);
 	return JSON.parse(json) as State;
 };
diff --git a/src/routes/edit.svelte b/src/routes/edit.svelte
index aa21f82a..afdd0f9a 100644
--- a/src/routes/edit.svelte
+++ b/src/routes/edit.svelte
@@ -82,7 +82,7 @@
 					startLineNumber: e.hash.loc.first_line,
 					startColumn: e.hash.loc.first_column,
 					endLineNumber: e.hash.loc.last_line,
-					endColumn: e.hash.loc.last_column + 1,
+					endColumn: (e.hash.loc.last_column as number) + 1,
 					message: e.str
 				};
 				errorMarkers.push(marker);