Javascript · Code with Hugo

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', { ...

#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 #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 ...

#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 ...

#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 ...

#JavaScript #web development

Avoid null/undefined in JavaScript arrays

How to avoid TypeError: Cannot read property ___ of undefined using Array.filter(Boolean) tl;dr: Array.filter(Boolean) filters out falsy values (null, undefined, 0, false, '') and avoids Cannot read property of undefined errors. Table of contents: ...

#JavaScript #tip

JavaScript array type check - “is array” vs object in-depth

Detecting Array vs Object in JavaScript with examples tl;dr To detect if something is an Array in JavaScript, use Array.isArray(somethingObjectToCheck). This post is a quarter useful, quarter history lesson, half quirky JavaScript exploration. Table of contents: ...

#JavaScript #vuejs #node

Post Frequency: from prototype to production with Vue + Node

If you want to ship, use the tools you know. — A lot of people Let’s apply that principle: I’m building Post Frequency/Accountable Blogging, I’m familiar with Vue and Node-based backends. Netlify makes frontend deployments trivial and I’ve settled on Dokku for ...