Simple AWS Lambda Container In-Memory Cache Controller for Node.js / ES6

handler.js

import { LambdaCacheController } from "libs/LambdaCacheController";

// make it out side handler to make it in-memory cachable in lambda container
const lambdaCache = new LambdaCacheController();

export async function main(event) {
    try {
        // get content from cache (if possible)
        let data = await lambdaCache.getValue();

        if (!data) {
            // fetch your data here
            const projects = await getItemsFromCollection("projects"); 
            if (!projects) throw Error("projects returned error");

            // save content to cache
            await lambdaCache.setValue(projects.items || []);

            // set your data to contain the cached value + expireIn meta data
            data = await lambdaCache.getValue();
        }

        // return data nicely
        return success({
            data: data.value,
            expiresIn: data.expiresIn,
        });
    } catch (e) {
        console.log(e);
        return failure(e);
    }
}

LambdaCacheController.js

export class LambdaCacheController {
    constructor() {
        this.value = null;
        this.timestamp = null;
        this.ttl = 3000000; // default 5 minutes
    }

    async getValue() {
        return new Promise((resolve, reject) => {
            try {
                const { timestamp, value, ttl } = this;
                const expiresIn = timestamp + ttl - Date.now();

                resolve(
                    value && timestamp && expiresIn > 0
                        ? {
                              value: JSON.parse(value),
                              expiresIn,
                          }
                        : null
                );
            } catch (e) {
                console.error(e);
                reject(e);
            }
        });
    }

    async setValue(valueToCache, timeToLive) {
        return new Promise((resolve, reject) => {
            try {
                this.value = JSON.stringify(valueToCache);
                this.timestamp = Date.now();
                if (timeToLive) this.ttl = timeToLive;

                resolve(true);
            } catch (e) {
                console.error(e);
                reject(e);
            }
        });
    }
}