cache-manager - adding back in ttl() function to get the expiration

Author: jaredwray

packages/cache-manager/src/index.ts

@@ -17,6 +17,7 @@ export type Cache = {
 	// eslint-disable-next-line @typescript-eslint/ban-types
 	get: <T>(key: string) => Promise<T | null>;
 	mget: <T>(keys: string[]) => Promise<[T]>;
+	ttl: (key: string) => Promise<number | undefined>;
 	set: <T>(key: string, value: T, ttl?: number) => Promise<T>;
 	mset: <T>(
 		list: Array<{
@@ -105,6 +106,41 @@ export const createCache = (options?: CreateCacheOptions): Cache => {
 		return result as [T];
 	};
 
+	// eslint-disable-next-line @typescript-eslint/ban-types
+	const ttl = async (key: string): Promise<number | null> => {
+		let result = null;
+
+		if (nonBlocking) {
+			try {
+				result = await Promise.race(stores.map(async store => store.get(key, {raw: true})));
+				if (result === undefined) {
+					return null;
+				}
+			} catch (error) {
+				eventEmitter.emit('ttl', {key, error});
+			}
+		} else {
+			for (const store of stores) {
+				try {
+					const cacheValue = await store.get(key, {raw: true});
+					if (cacheValue !== undefined) {
+						result = cacheValue;
+						eventEmitter.emit('ttl', {key, value: result});
+						break;
+					}
+				} catch (error) {
+					eventEmitter.emit('ttl', {key, error});
+				}
+			}
+		}
+
+		if (result?.expires) {
+			return result.expires;
+		}
+
+		return null;
+	};
+
 	const set = async <T>(stores: Keyv[], key: string, value: T, ttl?: number) => {
 		try {
 			if (nonBlocking) {
@@ -281,6 +317,7 @@ export const createCache = (options?: CreateCacheOptions): Cache => {
 	return {
 		get,
 		mget,
+		ttl,
 		set: async <T>(key: string, value: T, ttl?: number) => set(stores, key, value, ttl),
 		mset: async <T>(list: Array<{key: string; value: T; ttl?: number}>) => mset(stores, list),
 		del,

packages/cache-manager/test/ttl.test.ts

@@ -0,0 +1,71 @@
+import {Keyv} from 'keyv';
+import {
+	beforeEach, describe, expect, it,
+} from 'vitest';
+import {faker} from '@faker-js/faker';
+import {createCache} from '../src/index.js';
+import {sleep} from './sleep.js';
+
+describe('get', () => {
+	let keyv: Keyv;
+	let cache: ReturnType<typeof createCache>;
+	let ttl = 500;
+	const data = {key: '', value: ''};
+
+	beforeEach(async () => {
+		data.key = faker.string.alpha(20);
+		data.value = faker.string.sample();
+		ttl = faker.number.int({min: 500, max: 1000});
+		keyv = new Keyv();
+		cache = createCache({stores: [keyv]});
+	});
+
+	it('basic', async () => {
+		await cache.set(data.key, data.value);
+		await expect(cache.ttl(data.key)).resolves.toEqual(null);
+	});
+
+	it('expired', async () => {
+		await cache.set(data.key, data.value, ttl);
+		await sleep(ttl + 100);
+		await expect(cache.ttl(data.key)).resolves.toEqual(null);
+	});
+
+	it('error', async () => {
+		await cache.set(data.key, data.value);
+		keyv.get = () => {
+			throw new Error('get error');
+		};
+
+		await expect(cache.ttl(data.key)).resolves.toEqual(null);
+	});
+	it('error on non-blocking enabled', async () => {
+		const secondKeyv = new Keyv();
+		keyv.get = () => {
+			throw new Error('get error');
+		};
+
+		const cache = createCache({stores: [keyv, secondKeyv], nonBlocking: true});
+		await cache.set(data.key, data.value);
+		await expect(cache.ttl(data.key)).resolves.toEqual(null);
+	});
+	it('gets the expiration of a key', async () => {
+		await cache.set(data.key, data.value, ttl);
+		const expiration = Date.now() + ttl;
+		await expect(cache.ttl(data.key)).resolves.toBeGreaterThanOrEqual(expiration - 100);
+	});
+
+	it('gets the expiration of a key with nonBlocking', async () => {
+		const secondKeyv = new Keyv();
+		const cache = createCache({stores: [keyv, secondKeyv], nonBlocking: true});
+		await cache.set(data.key, data.value, ttl);
+		const expiration = Date.now() + ttl;
+		await expect(cache.ttl(data.key)).resolves.toBeGreaterThanOrEqual(expiration - 100);
+	});
+
+	it('gets null of a key with nonBlocking', async () => {
+		const secondKeyv = new Keyv();
+		const cache = createCache({stores: [keyv, secondKeyv], nonBlocking: true});
+		await expect(cache.ttl('non-block-bad-key1')).resolves.toEqual(null);
+	});
+});