@aller/cyclops-frontend-react

cyclops-front

Front end abstractions for interacting with the cyclops API

"No. Not plan B. Plan 2. 'Plan B' implies we only have 26."

-- Cyclops to Mayor Sadie Sinclair (Uncanny X-Men Vol 1 541)

Design

While all datatypes returned in a CyclopsResponse are readonly, we can think of cyclops as returning two types of data, namely transient user state and cachable public data. For example the state of a User may change due to their interaction with the website, updating a subscription for example. On the other hand there is cachable data like the Catalogue (a big old JSON data structure that contains all Aller Media brands, products and deals) that is not expected to change due to user interation and is infact public (one can perform a GET request without any cookies)

For this reason cyclops-frontend-react exposes two separate contexts CyclopsUserContext and CyclopsDataContext.

CyclopsUserContext

ICyclopsUserContext; // interface
CyclopsUserContextProvider;
useCyclopsUserContext: () => ICyclopsUserContext;

The cyclopsUserContext ensures that any action that requires the User data to be reloaded is performed automatically. This means that you do not have to worry about the User object becoming stale. As an example:

import {
  useCyclopsUserContext,
  ICyclopsUserContext,
  CyclopsResponse,
  IUser,
} from 'cyclops-frontend-react';

export const MyComponent = () => {
  const context: ICyclopsUserContext = useCyclopsUserContext();
  /* the userResponse is guaranteed to have a boolean value `.loading` */
  if (context.user.loading) {
    return <div>you spin me right round baby right round</div>;
  }
  if (context.user.error) {
    /*
    cyclops-front does not currently try to hide the errors
    insead it catches and wraps them in the response.
    Note that an error may be due to the network - or due to
    a schema validation error.
    */
    return <div>Ooops!</div>;
  }
  if (context.user.result) {
    return <div>Hello {context.user.result.fullName}</div>;
  }
  return <div>The unknown user</div>;
};

managed sessions

If you only need to add a login button to your page then you can use the CyclopsSessionButton. This is a compenent that relies upon the existance of the CyclopsUserContextProvider and handles login status for you.

CyclopsDataContext

ICyclopsDataContext; // interface
CyclopsDataContextProvider;
useCyclopsDataContext: () => ICyclopsDataContext;

The data context currently only contains the Catalogue datastructure. This data can only be fetched as is cachable. This context is most likely only interesting if you are working on the minside webpage.

Contracts (JSON spec)

One of the main responsibilities of this library is to provide a contract with cyclops-api - your one stop shop for all user related interactions.

Every response value from the api is verified using the ajv libray (JSON schema).

When an object returned from the cyclops-api is exposed to the user of this library it returned as a CyclopsResponse type. This actually means that the responses are not returned as Promises.

export interface CyclopsError {
  error: any;
}

export interface CyclopsResponse<T> {
  loading: boolean;
  result?: T;
  error?: CyclopsError;
}

Developing

• When developing this library it is important to bear in mind that it is your responsibility to match typescript interfaces to the appropriate JSON schemas.

TSDX React User Guide

Congrats! You just saved yourself hours of work by bootstrapping this project with TSDX. Let’s get you oriented with what’s here and how to use it.

This TSDX setup is meant for developing React components (not apps!) that can be published to NPM. If you’re looking to build an app, you should use create-react-app, razzle, nextjs, gatsby, or react-static.

If you’re new to TypeScript and React, checkout this handy cheatsheet

Commands

TSDX scaffolds your new library inside /src, and also sets up a Parcel-based playground for it inside /example.

The recommended workflow is to run TSDX in one terminal:

npm start # or yarn start

This builds to /dist and runs the project in watch mode so any edits you save inside src causes a rebuild to /dist.

Then run the example inside another:

cd example
npm i # or yarn to install dependencies
npm start # or yarn start

The default example imports and live reloads whatever is in /dist, so if you are seeing an out of date component, make sure TSDX is running in watch mode like we recommend above. No symlinking required, we use Parcel's aliasing.

To do a one-off build, use npm run build or yarn build.

To run tests, use npm test or yarn test.

Configuration

Code quality is set up for you with prettier, husky, and lint-staged. Adjust the respective fields in package.json accordingly.

Jest

Jest tests are set up to run with npm test or yarn test. This runs the test watcher (Jest) in an interactive mode. By default, runs tests related to files changed since the last commit.

Setup Files

This is the folder structure we set up for you:

/example
  index.html
  index.tsx       # test your component here in a demo app
  package.json
  tsconfig.json
/src
  index.tsx       # EDIT THIS
/test
  blah.test.tsx   # EDIT THIS
.gitignore
package.json
README.md         # EDIT THIS
tsconfig.json

React Testing Library

We do not set up react-testing-library for you yet, we welcome contributions and documentation on this.

Rollup

TSDX uses Rollup v1.x as a bundler and generates multiple rollup configs for various module formats and build settings. See Optimizations for details.

TypeScript

tsconfig.json is set up to interpret dom and esnext types, as well as react for jsx. Adjust according to your needs.

Continuous Integration

Travis

to be completed

Circle

to be completed

Optimizations

Please see the main tsdx optimizations docs. In particular, know that you can take advantage of development-only optimizations:

// ./types/index.d.ts
declare var __DEV__: boolean;

// inside your code...
if (__DEV__) {
  console.log('foo');
}

You can also choose to install and use invariant and warning functions.

Module Formats

CJS, ESModules, and UMD module formats are supported.

The appropriate paths are configured in package.json and dist/index.js accordingly. Please report if any issues are found.

Using the Playground

cd example
npm i # or yarn to install dependencies
npm start # or yarn start

The default example imports and live reloads whatever is in /dist, so if you are seeing an out of date component, make sure TSDX is running in watch mode like we recommend above. No symlinking required!

Deploying the Playground

The Playground is just a simple Parcel app, you can deploy it anywhere you would normally deploy that. Here are some guidelines for manually deploying with the Netlify CLI (npm i -g netlify-cli):

cd example # if not already in the example folder
npm run build # builds to dist
netlify deploy # deploy the dist folder

Alternatively, if you already have a git repo connected, you can set up continuous deployment with Netlify:

netlify init
# build command: yarn build && cd example && yarn && yarn build
# directory to deploy: example/dist
# pick yes for netlify.toml

Named Exports

Per Palmer Group guidelines, always use named exports. Code split inside your React app instead of your React library.

Including Styles

There are many ways to ship styles, including with CSS-in-JS. TSDX has no opinion on this, configure how you like.

For vanilla CSS, you can include it at the root directory and add it to the files section in your package.json, so that it can be imported separately by your users and run through their bundler's loader.

Publishing to NPM

We recommend using np.

Usage with Lerna

When creating a new package with TSDX within a project set up with Lerna, you might encounter a Cannot resolve dependency error when trying to run the example project. To fix that you will need to make changes to the package.json file inside the example directory.

The problem is that due to the nature of how dependencies are installed in Lerna projects, the aliases in the example project's package.json might not point to the right place, as those dependencies might have been installed in the root of your Lerna project.

Change the alias to point to where those packages are actually installed. This depends on the directory structure of your Lerna project, so the actual path might be different from the diff below.

   "alias": {
-    "react": "../node_modules/react",
-    "react-dom": "../node_modules/react-dom"
+    "react": "../../../node_modules/react",
+    "react-dom": "../../../node_modules/react-dom"
   },

An alternative to fixing this problem would be to remove aliases altogether and define the dependencies referenced as aliases as dev dependencies instead. However, that might cause other problems.