Refactor repository layer

- Consistent use of arrow functions - Simpler naming - Extract query creation
CodeYourFuture · Aug 3, 2023 · 4d63db3 · 4d63db3
1 parent 3ca380e
commit 4d63db3
Show file tree

Hide file tree

Showing 7 changed files with 115 additions and 71 deletions.
diff --git a/server/db.js b/server/db.js
@@ -1,10 +1,19 @@
 import pgSession from "connect-pg-simple";
 import session, { MemoryStore } from "express-session";
 import { Pool } from "pg";
+import format from "pg-format";
 
 import config from "./utils/config";
 import logger from "./utils/logger";
 
+const pool = new Pool({
+	connectionString: config.dbUrl,
+	connectionTimeoutMillis: 5_000,
+	ssl: config.dbUrl.includes("localhost")
+		? false
+		: { rejectUnauthorized: false },
+});
+
 /**
  * Access this with `import db from "path/to/db";` then use it with
  * `await db.query("<SQL>", [...<variables>])`.
@@ -20,34 +29,6 @@ export default {
 	},
 };
 
-/**
- * {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals#tagged_templates Tagged template}
- * to turn a mutliline query in backticks into a single line.
- * @example
- * const myQuery = singleLine`
- *     SELECT *
- *     FROM some_table
- *     WHERE some_field = $1;
- * `;
- * @param {string} query
- * @returns {string}
- */
-export function singleLine([query]) {
-	return query
-		.trim()
-		.split("\n")
-		.map((line) => line.trim())
-		.join(" ");
-}
-
-const pool = new Pool({
-	connectionString: config.dbUrl,
-	connectionTimeoutMillis: 5_000,
-	ssl: config.dbUrl.includes("localhost")
-		? false
-		: { rejectUnauthorized: false },
-});
-
 export const connectDb = async () => {
 	let client;
 	try {
@@ -62,7 +43,11 @@ export const connectDb = async () => {
 
 export const disconnectDb = () => pool.end();
 
-export function getSessionStore() {
+export const ErrorCodes = {
+	UNIQUE_VIOLATION: "23505",
+};
+
+export const getSessionStore = () => {
 	const store = config.sessionStore;
 	switch (store) {
 		case "memory":
@@ -72,4 +57,54 @@ export function getSessionStore() {
 		default:
 			throw new Error(`unknown store type: ${store}`);
 	}
+};
+
+/**
+ * Create an insert query for the given table name and columns.
+ * @param {string} tableName
+ * @param {string[]} columns
+ * @returns {string}
+ */
+export function insertQuery(tableName, columns) {
+	return format(
+		"INSERT INTO %I (%s) VALUES (%s) RETURNING *;",
+		tableName,
+		columns.map((column) => format.ident(column)).join(", "),
+		columns.map((_, index) => `$${index + 1}`).join(", ")
+	);
+}
+
+/**
+ * {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals#tagged_templates Tagged template}
+ * to turn a mutliline query in backticks into a single line.
+ * @example
+ * const myQuery = singleLine`
+ *     SELECT *
+ *     FROM some_table
+ *     WHERE some_field = $1;
+ * `;
+ * @param {string} query
+ * @returns {string}
+ */
+export function singleLine([query]) {
+	return query
+		.trim()
+		.split("\n")
+		.map((line) => line.trim())
+		.join(" ");
+}
+/**
+ * Create an update query for the given table name and columns.
+ * @param {string} tableName
+ * @param {string[]} columns
+ * @returns {string}
+ */
+export function updateQuery(tableName, columns) {
+	return format(
+		"UPDATE %I SET %s WHERE id = $1 RETURNING *;",
+		tableName,
+		columns
+			.map((column, index) => `${format.ident(column)} = $${index + 2}`)
+			.join(", ")
+	);
 }
diff --git a/server/resources/resourcesRepository.js b/server/resources/resourcesRepository.js
@@ -1,51 +1,55 @@
-import db, { singleLine } from "../db";
+import db, { ErrorCodes, insertQuery, singleLine, updateQuery } from "../db";
 
 import { DuplicateResource } from "./resourcesService";
 
+const resourceQuery = singleLine`
+	SELECT r.*, t.name as topic_name
+	FROM resources as r
+	LEFT JOIN topics as t
+	ON r.topic = t.id
+`;
+
 export const add = async ({ description, source, title, topic, url }) => {
 	try {
 		const {
 			rows: [created],
 		} = await db.query(
-			"INSERT INTO resources (description, source, title, topic, url) VALUES ($1, $2, $3, $4, $5) RETURNING *;",
+			insertQuery("resources", [
+				"description",
+				"source",
+				"title",
+				"topic",
+				"url",
+			]),
 			[description, source, title, topic, url]
 		);
 		return created;
 	} catch (err) {
-		if (err.code === "23505" /** unique_violation */) {
+		if (err.code === ErrorCodes.UNIQUE_VIOLATION) {
 			throw new DuplicateResource();
 		}
 		throw err;
 	}
 };
 
+export const findAll = async () => {
+	const { rows } = await db.query(resourceQuery);
+	return rows;
+};
+
 export const findOne = async (id) => {
 	const {
 		rows: [resource],
 	} = await db.query(`${resourceQuery} WHERE r.id = $1;`, [id]);
 	return resource;
 };
 
-export const getAll = async ({ draft }) => {
-	const { rows } = await db.query(
-		draft ? `${resourceQuery};` : `${resourceQuery} WHERE r.draft = false;`
-	);
-	return rows;
-};
-
 export const update = async (id, { draft, publication, publisher }) => {
 	const {
 		rows: [updated],
 	} = await db.query(
-		"UPDATE resources SET draft = $2, publication = $3, publisher = $4 WHERE id = $1 RETURNING *;",
+		updateQuery("resources", ["draft", "publication", "publisher"]),
 		[id, draft, publication, publisher]
 	);
 	return updated;
 };
-
-const resourceQuery = singleLine`
-	SELECT r.*, t.name as topic_name
-	FROM resources as r
-	LEFT JOIN topics as t
-	ON r.topic = t.id
-`;
diff --git a/server/resources/resourcesService.js b/server/resources/resourcesService.js
@@ -18,7 +18,11 @@ export const create = async (resource) => {
 };
 
 export async function getAll(includeDrafts) {
-	return await repository.getAll({ draft: includeDrafts });
+	const resources = await repository.findAll();
+	if (includeDrafts) {
+		return resources;
+	}
+	return resources.filter(({ draft }) => draft === false);
 }
 
 export async function publish(resourceId, publisherId) {

diff --git a/server/topics/topicsRepository.js b/server/topics/topicsRepository.js
@@ -1,13 +1,13 @@
 import db from "../db";
 
-export async function findOne(id) {
+export const findAll = async () => {
+	const { rows } = await db.query("SELECT * FROM topics;");
+	return rows;
+};
+
+export const findOne = async (id) => {
 	const {
 		rows: [topic],
 	} = await db.query("SELECT * FROM topics WHERE id = $1;", [id]);
 	return topic;
-}
-
-export async function getAll() {
-	const { rows } = await db.query("SELECT * FROM topics;");
-	return rows;
-}
+};
diff --git a/server/topics/topicsService.js b/server/topics/topicsService.js
@@ -7,7 +7,7 @@ export class MissingTopic extends Error {
 }
 
 export async function getAll() {
-	return await repository.getAll();
+	return await repository.findAll();
 }
 
 export async function getById(id) {

diff --git a/server/users/usersRepository.js b/server/users/usersRepository.js
@@ -1,21 +1,27 @@
-import db from "../db";
+import db, { insertQuery } from "../db";
 
 export const add = async ({ email, gitHubId, name }) => {
 	const {
 		rows: [created],
-	} = await db.query(
-		"INSERT INTO users (email, github_id, name) VALUES ($1, $2, $3) RETURNING *;",
-		[email, gitHubId, name]
-	);
+	} = await db.query(insertQuery("users", ["email", "github_id", "name"]), [
+		email,
+		gitHubId,
+		name,
+	]);
 	return created;
 };
 
-export async function findOne(id) {
+export const findAll = async () => {
+	const { rows } = await db.query("SELECT * FROM users;");
+	return rows;
+};
+
+export const findOne = async (id) => {
 	const {
 		rows: [found],
 	} = await db.query("SELECT * FROM users WHERE id = $1;", [id]);
 	return found;
-}
+};
 
 export const findOneByGitHubId = async (id) => {
 	const {
@@ -24,17 +30,12 @@ export const findOneByGitHubId = async (id) => {
 	return found;
 };
 
-export async function getAll() {
-	const { rows } = await db.query("SELECT * FROM users;");
-	return rows;
-}
-
-export async function update(id, { is_admin }) {
+export const update = async (id, { is_admin }) => {
 	const {
 		rows: [updated],
 	} = await db.query(
 		"UPDATE users SET is_admin = $2 WHERE id = $1 RETURNING *;",
 		[id, is_admin]
 	);
 	return updated;
-}
+};
diff --git a/server/users/usersService.js b/server/users/usersService.js
@@ -15,7 +15,7 @@ export async function findByGitHubId(id) {
 }
 
 export async function getAll() {
-	return await repository.getAll();
+	return await repository.findAll();
 }
 
 export async function getById(id) {