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There’s some nice use-cases for snapshot tests outside of the well-travelled React/Vue UI component ones. In other words, although React and Vue testing with snapshots is pretty well documented, that’s not the only place they’re useful. As a rule of thumb, you could replace a lot of unit tests that assert on with specific data with snapshot tests. We have the following pros for snapshot tests: - the match data is stored in a separate file so it’s harder to lose track of things, eg. ...

Easily deploying to multiple environments in a simple manner using GitHub, CircleCI and Heroku. Continuous Integration is awesome, but sometimes you need a buffer between auto-deploying things on merge and the production release. To do that with CircleCI requires some git branch-wrangling and a few lines of bash scripting. We’ll imagine a scenario where a deploy is trivial (ie. we’ll pretend we’re using Heroku). For more complicated build steps we should still be able to follow similar principles. ...

A bash cheat sheet for developers who just want to get by. Writing setup, CI and deployment flows means a bit of the old bash scripting. Despite my deep interest in the intricacies of Bash (/sarcasm), I’ve kept hitting up Google and StackOverflow for solutions to the same couple of situations. To avoid having to do this again myself and for your reading pleasure, here they are. ...

As part of adding integration tests to an app on CircleCI I ran into the following issues: redis-cli’s API has changed from version 2 to 3 to 4 ie. this works in v4 redis-cli -u ${REDIS_URL} but doesn’t in v2 the “only way” to install redis-cli is through a redis-tools or redis-server install and I only need redis-cli not the server or any other tools What follows is how not to install redis-cli and then how to install redis-cli latest, properly. ...

There always comes a point in a web application’s life where an operation is best served in the background, this is where queues come in. There are a few queuing solutions in Node. None of them are ridiculously dominant, eg. Kue, RSMQ, Bee Queue, bull. The issue with Kue, RSMQ and Bee Queue was its use of a done callback as the recommended API. Bull https://github.com/OptimalBits/bull is a premium Queue package for handling jobs and messages in NodeJS. It’s backed by Redis and is pretty feature-rich. Most of all, it leverages a Promise-based processing API which means async/await. We’ll walk through an application that sends webhooks with a given payload to a set of URLs. ...

When using docker-compose, it’s good practice to make anything that relies on Postgres wait for it to be up before launching. This avoids connection issues inside the app. This post walks through how to deliver this functionality both as a CLI and a module that works both as a CommonJS module (require) and ES modules, without transpilation. “A fast, production ready, zero-dependency ES module loader for Node 6+!” is esm’s promise. From this sample project, it’s worked. ...

Here is the implementation for a function that takes a Promise-based fetch function and a function that decides if a response has been successful (from a polling perspective) and polls the fetch function until the isSuccess function returns true: ...

There are situations where Date.now is used in application code. That code needs to be tested, and it’s always a struggle to remember how to mock Date.now. Here is the magic snippet: ...

CSS tip: object-fit your images. To have an image that doesn’t try to stretch to its width/height the classic CSS is as follows: ...

Let’s say we want to measure the depth of we have an object with mixed nested arrays/objects like so: ...