mkirvela / safer-globe-arms-report

SaferGlobe Arms Report Visualisation

SaferGlobe Arms Report

Visualizing data relating to global arms trading, especially with respect to Finland.

This project was bootstrapped with Create React App.

To see the full documentation regarding that, go here. The salient points are reproduced below, along with important custom setup documentation.

Installation

This project uses yarn. Install it as described here https://yarnpkg.com/lang/en/ if you haven't already.

To install this project, simply clone the repo and run yarn;

e.g.

git clone https://github.com/futurice/safer-globe-arms-report.git
cd safer-globe-arms-report
yarn

Local Development

In the project directory, you can run:

yarn start

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

The page will reload if you make edits.
You will also see any lint errors in the console.

Tooling setup

This project uses ESLint integrated with prettier, which verifies and formats your code so you don't have to do it manually. You should have your editor set up to display lint errors and automatically fix those which it is possible to fix. See http://eslint.org/docs/user-guide/integrations.

The author of this document recommends Visual Studio Code, which this project is already set up to work with. Install it from here and then install this eslint plugin and you should be good to go.

In addition, this project uses lint-staged as a pre-commit hook to help prevent you from committing bad code. Use the --no-verify argument to git commit if you really really need to commit code which fails linting for some reason.

Production workflow

We use Heroku for deployment. Log in here if you need to, but you probably don't need to unless we run out of uptime credit and you need to buy some. The username and password are in the password safe.

The master branch is deployed automatically from github to https://safer-globe-arms-report.herokuapp.com/, so avoid pushing changes directly to master, especially after the point when we have something valuable running.

Pull requests are deployed to Heroku 'review' apps. A minute or two after submitting a pull request you can find a button on the PR page which says "View deployment". This link can be shared with stakeholders and is available for 5 days after the most recent activity on the pull request.

So the workflow should be roughly as follows:

1. Make changes locally (see Local Development)
2. Commit to a non-master branch. Use git-flow branch naming like feature/interactive-map or fix/scrolling-bug
3. Push to github
4. In github UI, make a PR from the branch you just pushed to master
5. View deployment to make sure it works
6. If you need to make changes, push them to the same branch and go back to step 5
7. When changes are approved, merge into master

Debugging in the Editor

This feature is currently only supported by Visual Studio Code editor.

Visual Studio Code supports debugging out of the box with Create React App. This enables you as a developer to write and debug your React code without leaving the editor, and most importantly it enables you to have a continuous development workflow, where context switching is minimal, as you don’t have to switch between tools.

You would need to have the latest version of VS Code and VS Code Chrome Debugger Extension installed.

Then add the block below to your launch.json file and put it inside the .vscode folder in your app’s root directory.

{
  "version": "0.2.0",
  "configurations": [{
    "name": "Chrome",
    "type": "chrome",
    "request": "launch",
    "url": "http://localhost:3000",
    "webRoot": "${workspaceRoot}/src",
    "userDataDir": "${workspaceRoot}/.vscode/chrome",
    "sourceMapPathOverrides": {
      "webpack:///src/*": "${webRoot}/*"
    }
  }]
}

Start your app by running yarn start, and start debugging in VS Code by pressing F5 or by clicking the green debug icon. You can now write code, set breakpoints, make changes to the code, and debug your newly modified code—all from your editor.

Adding a Stylesheet

This project setup uses Webpack for handling all assets. Webpack offers a custom way of “extending” the concept of import beyond JavaScript. To express that a JavaScript file depends on a CSS file, you need to import the CSS from the JavaScript file:

Button.css

.Button {
  padding: 20px;
}

Button.js

import React, { Component } from 'react';
import './Button.css'; // Tell Webpack that Button.js uses these styles

class Button extends Component {
  render() {
    // You can use them as regular CSS styles
    return <div className="Button" />;
  }
}

This is not required for React but many people find this feature convenient. You can read about the benefits of this approach here. However you should be aware that this makes your code less portable to other build tools and environments than Webpack.

In development, expressing dependencies this way allows your styles to be reloaded on the fly as you edit them. In production, all CSS files will be concatenated into a single minified .css file in the build output.

If you are concerned about using Webpack-specific semantics, you can put all your CSS right into src/index.css. It would still be imported from src/index.js, but you could always remove that import if you later migrate to a different build tool.

Post-Processing CSS

This project setup minifies your CSS and adds vendor prefixes to it automatically through Autoprefixer so you don’t need to worry about it.

For example, this:

.App {
  display: flex;
  flex-direction: row;
  align-items: center;
}

becomes this:

.App {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: horizontal;
  -webkit-box-direction: normal;
      -ms-flex-direction: row;
          flex-direction: row;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
}

If you need to disable autoprefixing for some reason, follow this section.

Adding Images, Fonts, and Files

With Webpack, using static assets like images and fonts works similarly to CSS.

You can import a file right in a JavaScript module. This tells Webpack to include that file in the bundle. Unlike CSS imports, importing a file gives you a string value. This value is the final path you can reference in your code, e.g. as the src attribute of an image or the href of a link to a PDF.

To reduce the number of requests to the server, importing images that are less than 10,000 bytes returns a data URI instead of a path. This applies to the following file extensions: bmp, gif, jpg, jpeg, and png. SVG files are excluded due to #1153.

Here is an example:

import React from 'react';
import logo from './logo.png'; // Tell Webpack this JS file uses this image

console.log(logo); // /logo.84287d09.png

function Header() {
  // Import result is the URL of your image
  return <img src={logo} alt="Logo" />;
}

export default Header;

This ensures that when the project is built, Webpack will correctly move the images into the build folder, and provide us with correct paths.

This works in CSS too:

.Logo {
  background-image: url(./logo.png);
}

Webpack finds all relative module references in CSS (they start with ./) and replaces them with the final paths from the compiled bundle. If you make a typo or accidentally delete an important file, you will see a compilation error, just like when you import a non-existent JavaScript module. The final filenames in the compiled bundle are generated by Webpack from content hashes. If the file content changes in the future, Webpack will give it a different name in production so you don’t need to worry about long-term caching of assets.

Please be advised that this is also a custom feature of Webpack.

It is not required for React but many people enjoy it (and React Native uses a similar mechanism for images).
An alternative way of handling static assets is described in the next section.

Using the public Folder

Note: this feature is available with react-scripts@0.5.0 and higher.

Changing the HTML

The public folder contains the HTML file so you can tweak it, for example, to set the page title. The <script> tag with the compiled code will be added to it automatically during the build process.

Adding Assets Outside of the Module System

You can also add other assets to the public folder.

Note that we normally encourage you to import assets in JavaScript files instead. For example, see the sections on adding a stylesheet and adding images and fonts. This mechanism provides a number of benefits:

• Scripts and stylesheets get minified and bundled together to avoid extra network requests.
• Missing files cause compilation errors instead of 404 errors for your users.
• Result filenames include content hashes so you don’t need to worry about browsers caching their old versions.

However there is an escape hatch that you can use to add an asset outside of the module system.

If you put a file into the public folder, it will not be processed by Webpack. Instead it will be copied into the build folder untouched. To reference assets in the public folder, you need to use a special variable called PUBLIC_URL.

Inside index.html, you can use it like this:

<link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">

Only files inside the public folder will be accessible by %PUBLIC_URL% prefix. If you need to use a file from src or node_modules, you’ll have to copy it there to explicitly specify your intention to make this file a part of the build.

When you run yarn run build, Create React App will substitute %PUBLIC_URL% with a correct absolute path so your project works even if you use client-side routing or host it at a non-root URL.

In JavaScript code, you can use process.env.PUBLIC_URL for similar purposes:

render() {
  // Note: this is an escape hatch and should be used sparingly!
  // Normally we recommend using `import` for getting asset URLs
  // as described in “Adding Images and Fonts” above this section.
  return <img src={process.env.PUBLIC_URL + '/img/logo.png'} />;
}

Keep in mind the downsides of this approach:

• None of the files in public folder get post-processed or minified.
• Missing files will not be called at compilation time, and will cause 404 errors for your users.
• Result filenames won’t include content hashes so you’ll need to add query arguments or rename them every time they change.

When to Use the public Folder

Normally we recommend importing stylesheets, images, and fonts from JavaScript. The public folder is useful as a workaround for a number of less common cases:

• You need a file with a specific name in the build output, such as manifest.webmanifest.
• You have thousands of images and need to dynamically reference their paths.
• You want to include a small script like pace.js outside of the bundled code.
• Some library may be incompatible with Webpack and you have no other option but to include it as a <script> tag.

Note that if you add a <script> that declares global variables, you also need to read the next section on using them.

Using Global Variables

When you include a script in the HTML file that defines global variables and try to use one of these variables in the code, the linter will complain because it cannot see the definition of the variable.

You can avoid this by reading the global variable explicitly from the window object, for example:

const $ = window.$;

This makes it obvious you are using a global variable intentionally rather than because of a typo.

Alternatively, you can force the linter to ignore any line by adding // eslint-disable-line after it.

Running Tests

Create React App uses Jest as its test runner. To prepare for this integration, we did a major revamp of Jest so if you heard bad things about it years ago, give it another try.

Jest is a Node-based runner. This means that the tests always run in a Node environment and not in a real browser. This lets us enable fast iteration speed and prevent flakiness.

While Jest provides browser globals such as window thanks to jsdom, they are only approximations of the real browser behavior. Jest is intended to be used for unit tests of your logic and your components rather than the DOM quirks.

We recommend that you use a separate tool for browser end-to-end tests if you need them. They are beyond the scope of Create React App.

Filename Conventions

Jest will look for test files with any of the following popular naming conventions:

• Files with .js suffix in __tests__ folders.
• Files with .test.js suffix.
• Files with .spec.js suffix.

The .test.js / .spec.js files (or the __tests__ folders) can be located at any depth under the src top level folder.

We recommend to put the test files (or __tests__ folders) next to the code they are testing so that relative imports appear shorter. For example, if App.test.js and App.js are in the same folder, the test just needs to import App from './App' instead of a long relative path. Colocation also helps find tests more quickly in larger projects.

Command Line Interface

When you run yarn test, Jest will launch in the watch mode. Every time you save a file, it will re-run the tests, just like yarn start recompiles the code.

The watcher includes an interactive command-line interface with the ability to run all tests, or focus on a search pattern. It is designed this way so that you can keep it open and enjoy fast re-runs. You can learn the commands from the “Watch Usage” note that the watcher prints after every run:

Version Control Integration

By default, when you run yarn test, Jest will only run the tests related to files changed since the last commit. This is an optimization designed to make your tests runs fast regardless of how many tests you have. However it assumes that you don’t often commit the code that doesn’t pass the tests.

Jest will always explicitly mention that it only ran tests related to the files changed since the last commit. You can also press a in the watch mode to force Jest to run all tests.

Jest will always run all tests on a continuous integration server or if the project is not inside a Git or Mercurial repository.

Writing Tests

To create tests, add it() (or test()) blocks with the name of the test and its code. You may optionally wrap them in describe() blocks for logical grouping but this is neither required nor recommended.

Jest provides a built-in expect() global function for making assertions. A basic test could look like this:

import sum from './sum';

it('sums numbers', () => {
  expect(sum(1, 2)).toEqual(3);
  expect(sum(2, 2)).toEqual(4);
});

All expect() matchers supported by Jest are extensively documented here.
You can also use jest.fn() and expect(fn).toBeCalled() to create “spies” or mock functions.

Testing Components

There is a broad spectrum of component testing techniques. They range from a “smoke test” verifying that a component renders without throwing, to shallow rendering and testing some of the output, to full rendering and testing component lifecycle and state changes.

Different projects choose different testing tradeoffs based on how often components change, and how much logic they contain. If you haven’t decided on a testing strategy yet, we recommend that you start with creating simple smoke tests for your components:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

it('renders without crashing', () => {
  const div = document.createElement('div');
  ReactDOM.render(<App />, div);
});

This test mounts a component and makes sure that it didn’t throw during rendering. Tests like this provide a lot value with very little effort so they are great as a starting point, and this is the test you will find in src/App.test.js.

When you encounter bugs caused by changing components, you will gain a deeper insight into which parts of them are worth testing in your application. This might be a good time to introduce more specific tests asserting specific expected output or behavior.

If you’d like to test components in isolation from the child components they render, we recommend using shallow() rendering API from Enzyme. You can write a smoke test with it too:

yarn add --dev enzyme react-test-renderer

import React from 'react';
import { shallow } from 'enzyme';
import App from './App';

it('renders without crashing', () => {
  shallow(<App />);
});

Unlike the previous smoke test using ReactDOM.render(), this test only renders <App> and doesn’t go deeper. For example, even if <App> itself renders a <Button> that throws, this test will pass. Shallow rendering is great for isolated unit tests, but you may still want to create some full rendering tests to ensure the components integrate correctly. Enzyme supports full rendering with mount(), and you can also use it for testing state changes and component lifecycle.

You can read the Enzyme documentation for more testing techniques. Enzyme documentation uses Chai and Sinon for assertions but you don’t have to use them because Jest provides built-in expect() and jest.fn() for spies.

Here is an example from Enzyme documentation that asserts specific output, rewritten to use Jest matchers:

import React from 'react';
import { shallow } from 'enzyme';
import App from './App';

it('renders welcome message', () => {
  const wrapper = shallow(<App />);
  const welcome = <h2>Welcome to React</h2>;
  // expect(wrapper.contains(welcome)).to.equal(true);
  expect(wrapper.contains(welcome)).toEqual(true);
});

All Jest matchers are extensively documented here.
Nevertheless you can use a third-party assertion library like Chai if you want to, as described below.

Additionally, you might find jest-enzyme helpful to simplify your tests with readable matchers. The above contains code can be written simpler with jest-enzyme.

expect(wrapper).toContainReact(welcome)

To setup jest-enzyme with Create React App, follow the instructions for initializing your test environment to import jest-enzyme. Note that currently only version 2.x is compatible with Create React App.

yarn add --dev jest-enzyme@2.x

// src/setupTests.js
import 'jest-enzyme';

Focusing and Excluding Tests

You can replace it() with xit() to temporarily exclude a test from being executed.
Similarly, fit() lets you focus on a specific test without running any other tests.

Coverage Reporting

Jest has an integrated coverage reporter that works well with ES6 and requires no configuration.
Run yarn test -- --coverage (note extra -- in the middle) to include a coverage report like this:

Note that tests run much slower with coverage so it is recommended to run it separately from your normal workflow.

Again, more documentation available here.

License

See here