On a recent project, I had a need to create an FTP connection to a third-party server. Since we had no control over the server, I also wanted to setup a test FTP server that I could use to run our client against to make sure we could connect successfully. It turned out that implementing an FTP client and server in Node required a bit of work. We eventually solved this by using two libraries from NPM – jsftp for the client, and ftp-srv for the test server.
nodejs
Generating Excel Files using Node.js and ExcelJS
Recently, I was tasked with writing some code to generate Excel workbooks containing sales data. I implemented the code using a Node module called ExcelJS. I found that this module provides a simple interface to generating documents, and it also supports more advanced functions such as text formatting, borders, formulae, and more. Read more on Generating Excel Files using Node.js and ExcelJS…
Managing Data Loaders in Node.js with Shared State
When developing software, it’s always tough to work with caching. While my team appreciates the efficiencies that Data Loader can provide for applications, we still struggle with the same problems that always come up when caching queries, mainly invalidating caches when a data set has changed. Read more on Managing Data Loaders in Node.js with Shared State…
Eliminate Circular Dependencies from Your JavaScript Project
Circular dependencies (also known as cyclic dependencies) occur when two or more modules reference each other.
This could be a direct reference (A -> B -> A):
// file a.ts
import { b } from 'b';
...
export a;Read more on Eliminate Circular Dependencies from Your JavaScript Project…
Extending the Heroku Timeout in Node.js
Heroku will terminate a request connection if no data is sent back to the client within 30 seconds. From Heroku’s Router – HTTP timeouts documentation:
HTTP requests have an initial 30-second window in which the web process must return response data (either the completed response or some amount of response data to indicate that the process is active). Processes that do not send response data within the initial 30-second window will see an H12 error in their logs.
PDF Snapshot Testing with Node and GraphicsMagick
The task I am working on this week involves generating downloadable PDF files for customer and supplier orders. We’d like to drive the implementation using tests and be able to find any regressions in the code automatically.
After looking at different alternatives for accomplishing this, we decided to try a visual snapshot approach similar to the way Jest does snapshot testing.
Read more on PDF Snapshot Testing with Node and GraphicsMagick…
Optimizing GraphQL Queries with DataLoader
In my post about GraphQL and the Apollo server tools, I primarily focused on setting up a simple GraphQL schema and set of resolvers, but did not go much deeper. The main example in that post defined a findBy method which simulated hitting a database, but for the sake of brevity, this detail was largely overlooked.
Read more on Optimizing GraphQL Queries with DataLoader…
Timing Your Queries in Knex.js for Node.js
While developing web applications, I keep a close eye on performance issues, particularly in database queries. In my latest project, I’ve been using Knex.js, a SQL query builder for Node.js.
I developed a method of logging the queries executed by Knex.js as well as the execution times for each query. This method can be applied to nearly any application that uses Knex.js, and it uses a few features of Knex.js that I didn’t notice immediately, so I thought I’d share this small but useful bit of code.
Read more on Timing Your Queries in Knex.js for Node.js…
Debugging ES6 Code in Node.js
I recently decided to use Node.js for my current project, and I also thought it would be a good idea to start off using ES6 (properly known as ECMAScript 2015). ES6 was a major addition to the language, and it was just formalized in June 2015. Since then, there has been a lot of effort to add ES6 compatibility to browsers (and Node.js). Until there is unanimous support for ES6, which will likely be quite some time yet, developers who use ES6 are required to run their code through a transpiler in order to transform it into valid ES5 for browser compatibility.
Read more on Debugging ES6 Code in Node.js…
Bye-Bye, Sinon – Hello, testdouble
UPDATE: Justin Searls, the author of testdouble.js sent me an email with some notes on this post. I’ve added some his comments below to provide some additional context.
I’ve been working in JavaScript-land for the last little while, writing lots of Node.js code. Since I practice TDD, I’m always trying to keep my eye on the best new ways to test JavaScript code. Read more on Bye-Bye, Sinon – Hello, testdouble…