diff --git a/src/common/remote/activitypub/resolver.ts b/src/common/remote/activitypub/resolver.ts
index 43f0d63cb3..a167fa1339 100644
--- a/src/common/remote/activitypub/resolver.ts
+++ b/src/common/remote/activitypub/resolver.ts
@@ -7,55 +7,6 @@ type IResult = {
   object: IObject;
 };
 
-async function resolveUnrequestedOne(this: Resolver, value) {
-	if (typeof value !== 'string') {
-		return { resolver: this, object: value };
-	}
-
-	const resolver = new Resolver(this.requesting);
-
-	resolver.requesting.add(value);
-
-	const object = await request({
-		url: value,
-		headers: {
-			Accept: 'application/activity+json, application/ld+json'
-		},
-		json: true
-	});
-
-	if (object === null || (
-		Array.isArray(object['@context']) ?
-			!object['@context'].includes('https://www.w3.org/ns/activitystreams') :
-			object['@context'] !== 'https://www.w3.org/ns/activitystreams'
-	)) {
-		throw new Error();
-	}
-
-	return { resolver, object };
-}
-
-async function resolveCollection(this: Resolver, value) {
-	if (Array.isArray(value)) {
-		return value;
-	}
-
-	const resolved = typeof value === 'string' ?
-		await resolveUnrequestedOne.call(this, value) :
-		value;
-
-	switch (resolved.type) {
-	case 'Collection':
-		return resolved.items;
-
-	case 'OrderedCollection':
-		return resolved.orderedItems;
-
-	default:
-		return [resolved];
-	}
-}
-
 export default class Resolver {
 	private requesting: Set<string>;
 
@@ -63,12 +14,61 @@ export default class Resolver {
 		this.requesting = new Set(iterable);
 	}
 
+	private async resolveUnrequestedOne(value) {
+		if (typeof value !== 'string') {
+			return { resolver: this, object: value };
+		}
+
+		const resolver = new Resolver(this.requesting);
+
+		resolver.requesting.add(value);
+
+		const object = await request({
+			url: value,
+			headers: {
+				Accept: 'application/activity+json, application/ld+json'
+			},
+			json: true
+		});
+
+		if (object === null || (
+			Array.isArray(object['@context']) ?
+				!object['@context'].includes('https://www.w3.org/ns/activitystreams') :
+				object['@context'] !== 'https://www.w3.org/ns/activitystreams'
+		)) {
+			throw new Error();
+		}
+
+		return { resolver, object };
+	}
+
+	private async resolveCollection(value) {
+		if (Array.isArray(value)) {
+			return value;
+		}
+
+		const resolved = typeof value === 'string' ?
+			await this.resolveUnrequestedOne(value) :
+			value;
+
+		switch (resolved.type) {
+		case 'Collection':
+			return resolved.items;
+
+		case 'OrderedCollection':
+			return resolved.orderedItems;
+
+		default:
+			return [resolved];
+		}
+	}
+
 	public async resolve(value): Promise<Array<Promise<IResult>>> {
-		const collection = await resolveCollection.call(this, value);
+		const collection = await this.resolveCollection(value);
 
 		return collection
 			.filter(element => !this.requesting.has(element))
-			.map(resolveUnrequestedOne.bind(this));
+			.map(this.resolveUnrequestedOne.bind(this));
 	}
 
 	public resolveOne(value) {
@@ -76,11 +76,11 @@ export default class Resolver {
 			throw new Error();
 		}
 
-		return resolveUnrequestedOne.call(this, value);
+		return this.resolveUnrequestedOne(value);
 	}
 
 	public async resolveRemoteUserObjects(value) {
-		const collection = await resolveCollection.call(this, value);
+		const collection = await this.resolveCollection(value);
 
 		return collection.filter(element => !this.requesting.has(element)).map(element => {
 			if (typeof element === 'string') {
@@ -91,7 +91,7 @@ export default class Resolver {
 				}
 			}
 
-			return resolveUnrequestedOne.call(this, element);
+			return this.resolveUnrequestedOne(element);
 		});
 	}
 }