Operational Scripts

scaffolding for web applications

At Contiamo, we deal with a number of different UI projects written in TypeScript. Each project begins as a greenfield project and usually is scaffolded with starter scripts configured to handle things like code style settings, TypeScript compiler options, linting, precommit hooks on git, et cetera. This starter then grows organically, while its scaffolding scripts go through a number of tweaks.

The end result is an array of no-longer- starter TypeScript codebases that have distinct scaffolding and lack some type of general consistency, homogeny or glue. Instead, we'd like each project to be consistent in its scaffolding, from starter to production, in order to allow each member of our team to be able to immediately read and understand the TypeScript codebase, while abstracting away the complexity of maintaining and piecing together starter scaffolding: dev servers, linters, and other things.

While this starter is no silver bullet to end all onboarding and scalable maintainability, it is an attempt to remedy the problem in a way that is TypeScript first: Operational Scripts allows us to hit the ground running with TypeScript, handling all of the scaffolding around it, including: webpack packaging, development servers, linters taken care of with optimal settings.

Ideally, with this starter, everything just works so long as we have a reasonable project structure^[1].

• Getting Started
• Nuances
  • Build Script
  • Webpack
    • Function Webpack Configs
• Contributing
• Footnotes

Getting Started

• npm install @operational/scripts -D

Running this command will:

• Replace any scaffolding: TypeScript configuration (tsconfig.json), tslint.json and .prettierrc in your current project with our recommendations.

• Install a precommit hook that, before commit:
  • Adds a table of contents to Markdown
  • Lints TypeScript
  • Pretty prints everything it can process: TypeScript, Markdown, JavaScript and JSON
• Update your .gitignore to include some more files, or adds one if missing
• Add a public folder with a starter HTML template and a configuration file^[2].
• Adds the following scripts to your package.json only if they don't already exist:
  • start: runs webpack-serve with any extra configuration passed in as flags.
  • build: runs the TypeScript compiler and packages for npm. See Build Script for more info.
  • test: runs Jest with TypeScript integration.
  • prePublishOnly: checks if the "main" file in your package.json actually exists before publish.
• Updates your package's main file.
  • Our starter webpack configuration sets an output file path. We mirror this path in your package's main file.

Nuances

Creating Operational Scripts as scaffolding for our projects required making some interesting decisions about configuration. These are outlined here for transparency.

Build Script

At Contiamo, we develop web applications that run standalone, and compose into a suite of web applications that is our final product. In order to create these embeddable applications, we need a two-step build process:

1. Build for production and deployment: just a standalone, webpack -p web app.
2. Build for Contiamo UI: this packages the app and prepares it to be published to our internal npm registry, or the public registry if open source.

Running npm build in a package that uses Operational Scripts will run both steps in parallel. If your use case only requires one or the other, simply use the --for flag, specifying the target of the build: production or npm.

npm run build -- --for npm, or npm run build -- --for production will build just what you need.

Webpack

We still want to be flexible with Operational Scripts because our starter projects evolve, and as they evolve, we may need to extend the starter's scaffolding in certain ways: perhaps we need more granular control over the dev server? What if we have a different entry point? What if we want to use a newer TypeScript loader? Or a different contentBase for static assets?

For this reason, our Webpack configuration is patchable.

Simply place a webpack.config.js at the root of your project, and any settings in there will override our defaults. Any settings not in there will fall back to our defaults.

This allows some control, while abstracting away most other complexity.

Function Webpack Configs

In most common cases, webpack configurations are expressed as plain old JavaScript objects. However, in other cases, users might wish to use a function as a module.exported webpack configuration.

Operational Scripts works with this, but has one rule: the function must use reasonable default parameters. The reason for this, is that Operational Scripts merges its own webpack config with the return of the custom webpack configuration function. At the time it invokes this function, it has no idea what to pass in as arguments. Therefore, defaults make sense here.

If your use case requires something even more custom, perhaps going full custom without Operational Scripts might make more sense in that case. If you're unsure, you are always welcome to open an issue and we can have a chat about it.

Contributing

Issues, Pull Requests and extensions are welcome. No question is a silly question. Head on over to issues to see where you could get involved, or to open one that will help us further improve this project.

Footnotes

• [1] Reasonable Project Structure: your code lives in src at the root of your project.
• [2] config.js: at Contiamo, we try to expose some runtime configuration of our applications in order to have more flexible frontend deployments, allowing our Ops team to pass in certain configuration values as Kubernetes configmaps. This file is completely optional and does not need a place in your codebase: it can be safely deleted if you do not need it.