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JavaScript Object.defineProperty for a function: create mock object instances in Jest or AVA

This post goes through how to use Object.defineProperty to mock how constructors create methods, ie. non-enumerable properties that are functions. The gist of Object.defineProperty use with a function value boils down to: const obj = {} Object.defineProperty(obj, 'yes', { ...

#git #bash

Fix git “tip of your current branch is behind its remote counterpart” - 4 real-world solutions

When working with git a selection of GitLab, GitHub, BitBucket and rebase-trigger-happy colleagues/collaborators, it’s a rite of passage to see a message like the following: Pushing to [email protected]:some-project/some-repo.git To [email protected]:some-project/some-repo.git ! [rejec ...

#JavaScript #fetch

Pass cookies with axios or fetch requests

When sending requests from client-side JavaScript, by default cookies are not passed. By default, fetch won’t send or receive any cookies from the server, resulting in unauthenticated requests https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch Two Java ...

#Express #Node #jest #Testing #JavaScript

A testing guide for Express with request and response mocking/stubbing using Jest or sinon

To test an Express handler, it’s useful to know how to successfully mock/stub the request and response objects. The following examples will be written both using Jest and sinon (running in AVA). The rationale for this is the following. Jest is a very popular “all-in-one” testing ...

#Express #Node #JavaScript #deployment

12-factor Node.js application configuration management without the `config` npm package

The config npm package is great (npmjs.com/package/config), but it encourages confusing and non-12-factor-app-compliant patterns. We’ll look at some of the patterns it encourages and why they’ll bring you struggles down the road as well a simple, single-file, no-dependency way to ...

#bash #deployment #ci #tooling

Bash Cheatsheet: check if environment variables are set or file/symlinks exists + more

A bash scripting 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 t ...

#Node #JavaScript #Python

The comprehensive guide to integrating a Python/Ruby/PHP/shell script with Node.js using child_process.spawn

There are occasions when running a Python/Ruby/PHP shell script from Node.js is necessary. This post looks at best practices around leveraging child_process.spawn to encapsulate this call in Node.js/JavaScript. The goal here is to have an interoperability layer between Node.js an ...

#JavaScript #Node

Async JavaScript: history, patterns and gotchas

A look at the history, patterns and gotchas of asynchronous operations in JavaScript. We’ll go through the pros and cons of callbacks, Promises and async/await. Present some pitfalls to bear in mind as well as introducing how you would deal with certain situations. Live-cod ...

#deployment #dokku #MongoDB

Connect to MongoDB on Dokku with your local command line or Robo3T

The Dokku mongo plugin provides a mongo:connect command, which opens a tunnelled connection to you MongoDB instance on Dokku. This is how you can connect to your database using the tool of your choice, the examples will be using Robo3T. Table of Contents: ...

#Sequelize #Express #JavaScript #node

Sequelize Data Types: a practical guide

DataTypes are core to the Sequelize 4 library. This is a practical and complete guide to make up for the sparse Sequelize official documentation on the subject. First of all, DataTypes contains both the types and generators for default values: eg. NOW, UUIDV1 and UUIDV4 are speci ...