Accept empty input to SubredditConfig constructor (#66)

Co-authored-by: Erin <github@eritbh.me>

src/classes/SubredditConfig.test.ts

@@ -1,4 +1,36 @@
 import test from 'ava';
+import {DEFAULT_CONFIG} from '../helpers/config';
+import {SubredditConfig} from './SubredditConfig';
+
+test('constructor: accept empty input', t => {
+	t.assert(
+		new SubredditConfig() instanceof SubredditConfig,
+		'passing nothing to SubredditConfig constructor should return a SubredditConfig instance',
+	);
+
+	t.assert(
+		new SubredditConfig('') instanceof SubredditConfig,
+		'passing empty string to SubredditConfig constructor should return a SubredditConfig instance',
+	);
+});
+
+test('constructor: results of passing in nothing and empty input are identical', t => {
+	const configFromNothing = new SubredditConfig();
+	const configFromEmpty = new SubredditConfig('');
+
+	t.deepEqual(
+		configFromNothing.toJSON(),
+		configFromEmpty.toJSON(),
+		'SubredditConfig initiated with nothing vs empty should be identical',
+	);
+});
+
+test('constructor: on empty input, the default config is returned', t => {
+	const config = new SubredditConfig();
+	const configAsJson = config.toJSON();
+
+	t.deepEqual(configAsJson, DEFAULT_CONFIG, "SubredditConfig initiated with nothing should return default config");
+});
 
 test.todo('getAllNoteTypes');
 test.todo('getNoteType');

src/classes/SubredditConfig.ts

@@ -1,4 +1,5 @@
 import {
+	DEFAULT_CONFIG,
 	DEFAULT_USERNOTE_TYPES,
 	migrateConfigToLatestSchema,
 } from '../helpers/config';
@@ -15,8 +16,13 @@ import type {Usernote} from '../types/Usernote';
 export class SubredditConfig {
 	private data: RawSubredditConfig;
 
-	constructor (jsonString: string) {
-		this.data = migrateConfigToLatestSchema(JSON.parse(jsonString));
+	constructor (jsonString?: string) {
+		if (jsonString) {
+			this.data = migrateConfigToLatestSchema(JSON.parse(jsonString));
+		} else {
+			// TODO: the default config value isn't actually typed correctly, this needs to be cleaned up eventually
+			this.data = DEFAULT_CONFIG as unknown as RawSubredditConfig;
+		}
 	}
 
 	/** Returns all usernote types. */

src/classes/ToolboxClient.ts

@@ -1,4 +1,4 @@
-import {RedditAPIClient} from '@devvit/public-api';
+import {RedditAPIClient, WikiPage} from '@devvit/public-api';
 import {Usernote, UsernoteInit} from '../types/Usernote';
 import {SubredditConfig} from './SubredditConfig';
 import {Usernotes} from './Usernotes';
@@ -140,9 +140,24 @@ export class ToolboxClient {
 		await this.writeUsernotes(subreddit, notes, reason);
 	}
 
-	/** */
+	/**
+	 * Retrieves toolbox configuration for a subreddit.
+	 * @param subreddit Name of the subreddit to retrieve config for
+	 */
 	async getConfig (subreddit: string) {
-		const page = await this.reddit.getWikiPage(subreddit, TB_CONFIG_PAGE);
-		return new SubredditConfig(page.content);
+		let page: WikiPage | undefined;
+		try {
+			page = await this.reddit.getWikiPage(subreddit, TB_CONFIG_PAGE);
+		} catch (error) {
+			// Devvit throws an error when page is not present, but also
+			// sometimes for other reasons. Check if the page actually
+			// exists; if it doesn't we'll use the default config, but if it
+			// does then something else is wrong and we'll rethrow the error.
+			const allPages = await this.reddit.getWikiPages(subreddit);
+			if (allPages.includes(TB_CONFIG_PAGE)) {
+				throw error;
+			}
+		}
+		return new SubredditConfig(page?.content);
 	}
 }

src/helpers/config.ts

@@ -25,6 +25,20 @@ export const DEFAULT_USERNOTE_TYPES: readonly RawUsernoteType[] = [
 	{key: 'botban', color: 'black', text: 'Bot Ban'},
 ];
 
+/**
+ * Default subreddit configuration to use if subreddit doesnt have one.
+ * Empty strings are used in the default config by the plugin even though
+ * this doesn't match the type exactly.
+ */
+export const DEFAULT_CONFIG = {
+	ver: LATEST_KNOWN_CONFIG_SCHEMA,
+	domainTags: '',
+	removalReasons: '',
+	modMacros: '',
+	usernoteColors: '',
+	banMacros: '',
+};
+
 /**
  * Checks the schema version of raw subreddit config data and attempts to update
  * it to the latest known schema version if it's out of date. Throws an error if