Refactor frontend main page and badge-example code (#2441)

- The goal of this PR is:
    - Consume the new service-definition format. (#2397)
    - Make the frontend more readable.
- Behavior changes:
    - I changed the **Image** field in the markup modal to show only the path.
    - I added another click-to-select field below that shows the complete URL.
    - This made it easier to suppress the live badge preview while it contains placeholders like `:user` or `:gem`, a minor tweak discussed at #2427 (comment).
    - The search box now searches all categories, regardless of the current page. (This is an improvement, I would say.)
- I did not deliberately address performance, though I ripped out a bunch of anonymous functions and avoided re-filtering all the examples by category on every render, which I expect will not hurt. I haven't really tested this on a mobile connection and it'd be worth doing that.
- It would be great to have some tests of the components, though getting started with that seemed like a big project and I did not want to make this any larger than it already is.

It's a medium-sized refactor:

1. Replace `BadgeExamples`, `Category` and `Badge` component with a completely rewritten `BadgeExamples` component which renders a table of badges, and `CategoryHeading` and `CategoryHeadings` components.
2. Refactor `ExamplesPage` and `SearchResults` components into a new `Main` component.
3. Rewrite the data flow for `MarkupModal`. Rather than rely on unmounting and remounting the component to copy the badge URL into state, employ the `getDerivedStateFromProps` lifecycle method.
4. Remove `prepareExamples` and `all-badge-examples`.
5. Rewrite the `$suggest` schema to harmonize with the service definition format. It's not backward-compatible which means at deploy time there probably will be 10–20 minutes of downtime on that feature, between the first server deploy and the final gh-pages deploy.  🤷‍♂️ (We could leave the old version in place if it seems worth it.)
6. Added two new functions in `make-badge-url` with tests. I removed _most_ of the uses of the old functions, but there are some in parts of the frontend I didn't touch like the static and dynamic badge generators, and again I didn't want to make this any larger than it already is.
7. Fix a couple bugs in the service-definition export.

.eslintrc-frontend.yml

@@ -21,4 +21,4 @@ settings:
 rules:
   no-console: "error"
 
-  import/extensions: ["error", "never", { "json": "always" }]
+  import/extensions: ["error", "never", { "json": "always", "yml": "always" }]

doc/TUTORIAL.md

@@ -279,6 +279,9 @@ module.exports = class GemVersion extends BaseJsonService {
 
 Save, run `npm start`, and you can see it [locally](http://127.0.0.1:3000/).
 
+If you update `examples`, you don't have to restart the server. Run `npm run
+defs` in another terminal window and the frontend will update.
+
 ### (4.5) Write Tests <!-- Change the link below when you change the heading -->
 [write tests]: #45-write-tests 
 

frontend/components/badge-examples.js

@@ -1,149 +1,92 @@
 import React from 'react'
-import { Link } from 'react-router-dom'
 import PropTypes from 'prop-types'
-import classNames from 'classnames'
-import resolveBadgeUrl from '../lib/badge-url'
+import { badgeUrlFromPath, staticBadgeUrl } from '../../lib/make-badge-url'
 
-const Badge = ({
-  title,
-  exampleUrl,
-  previewUrl,
-  urlPattern,
-  documentation,
-  baseUrl,
-  longCache,
-  shouldDisplay = () => true,
-  onClick,
-}) => {
-  const handleClick = onClick
-    ? () =>
-        onClick({
-          title,
-          exampleUrl,
-          previewUrl,
-          urlPattern,
-          documentation,
-        })
-    : undefined
+export default class BadgeExamples extends React.Component {
+  static propTypes = {
+    definitions: PropTypes.array.isRequired,
+    baseUrl: PropTypes.string,
+    longCache: PropTypes.bool.isRequired,
+    onClick: PropTypes.func.isRequired,
+  }
+
+  renderExample(exampleData) {
+    const { baseUrl, longCache, onClick } = this.props
+    const { title, example, preview } = exampleData
+
+    let previewUrl
+    // There are two alternatives for `preview`. Refer to the schema in
+    // `services/service-definitions.js`.
+    if (preview.label !== undefined) {
+      const { label, message, color } = preview
+      previewUrl = staticBadgeUrl({ baseUrl, label, message, color })
+    } else {
+      const { path, queryParams } = preview
+      previewUrl = badgeUrlFromPath({ baseUrl, path, queryParams, longCache })
+    }
+
+    // There are two alternatives for `example`. Refer to the schema in
+    // `services/service-definitions.js`.
+    let exampleUrl
+    if (example.pattern !== undefined) {
+      const { pattern, namedParams, queryParams } = example
+      exampleUrl = badgeUrlFromPath({
+        baseUrl,
+        path: pattern,
+        namedParams,
+        queryParams,
+      })
+    } else {
+      const { path, queryParams } = example
+      exampleUrl = badgeUrlFromPath({ baseUrl, path, queryParams })
+    }
+
+    const key = `${title} ${previewUrl} ${exampleUrl}`
 
-  const previewImage = previewUrl ? (
-    <img
-      className={classNames('badge-img', { clickable: onClick })}
-      onClick={handleClick}
-      src={resolveBadgeUrl(previewUrl, baseUrl, { longCache })}
-      alt=""
-    />
-  ) : (
-    '\u00a0'
-  ) // non-breaking space
-  const resolvedExampleUrl = resolveBadgeUrl(
-    urlPattern || previewUrl,
-    baseUrl,
-    { longCache: false }
-  )
+    const handleClick = () => onClick(exampleData)
 
-  if (shouldDisplay()) {
     return (
-      <tr>
-        <th
-          className={classNames({ clickable: onClick })}
-          onClick={handleClick}
-        >
+      <tr key={key}>
+        <th className="clickable" onClick={handleClick}>
           {title}:
         </th>
-        <td>{previewImage}</td>
         <td>
-          <code
-            className={classNames({ clickable: onClick })}
+          <img
+            className="badge-img clickable"
             onClick={handleClick}
-          >
-            {resolvedExampleUrl}
+            src={previewUrl}
+            alt=""
+          />
+        </td>
+        <td>
+          <code className="clickable" onClick={handleClick}>
+            {exampleUrl}
           </code>
         </td>
       </tr>
     )
   }
-  return null
-}
-Badge.propTypes = {
-  title: PropTypes.string.isRequired,
-  exampleUrl: PropTypes.string,
-  previewUrl: PropTypes.string,
-  urlPattern: PropTypes.string,
-  documentation: PropTypes.string,
-  baseUrl: PropTypes.string,
-  longCache: PropTypes.bool.isRequired,
-  shouldDisplay: PropTypes.func,
-  onClick: PropTypes.func.isRequired,
-}
 
-const Category = ({ category, examples, baseUrl, longCache, onClick }) => {
-  if (examples.filter(example => example.shouldDisplay()).length === 0) {
-    return null
-  }
-  return (
-    <div>
-      <Link to={`/examples/${category.id}`}>
-        <h3 id={category.id}>{category.name}</h3>
-      </Link>
-      <table className="badge">
-        <tbody>
-          {examples.map(badgeData => (
-            <Badge
-              key={badgeData.key}
-              {...badgeData}
-              baseUrl={baseUrl}
-              longCache={longCache}
-              onClick={onClick}
-            />
-          ))}
-        </tbody>
-      </table>
-    </div>
-  )
-}
-Category.propTypes = {
-  category: PropTypes.shape({
-    id: PropTypes.string.isRequired,
-    name: PropTypes.string.isRequired,
-  }).isRequired,
-  examples: PropTypes.arrayOf(
-    PropTypes.shape({
-      title: PropTypes.string.isRequired,
-      exampleUrl: PropTypes.string,
-      previewUrl: PropTypes.string,
-      urlPattern: PropTypes.string,
-      documentation: PropTypes.string,
-    })
-  ).isRequired,
-  baseUrl: PropTypes.string,
-  longCache: PropTypes.bool.isRequired,
-  onClick: PropTypes.func.isRequired,
-}
+  render() {
+    const { definitions } = this.props
 
-const BadgeExamples = ({ categories, baseUrl, longCache, onClick }) => (
-  <div>
-    {categories.map((categoryData, i) => (
-      <Category
-        key={i}
-        {...categoryData}
-        baseUrl={baseUrl}
-        longCache={longCache}
-        onClick={onClick}
-      />
-    ))}
-  </div>
-)
-BadgeExamples.propTypes = {
-  categories: PropTypes.arrayOf(
-    PropTypes.shape({
-      category: Category.propTypes.category,
-      examples: Category.propTypes.examples,
-    })
-  ),
-  baseUrl: PropTypes.string,
-  longCache: PropTypes.bool.isRequired,
-  onClick: PropTypes.func.isRequired,
-}
+    if (!definitions) {
+      return null
+    }
+
+    const flattened = definitions.reduce((accum, current) => {
+      const { examples } = current
+      return accum.concat(examples)
+    }, [])
 
-export { Badge, BadgeExamples }
+    return (
+      <div>
+        <table className="badge">
+          <tbody>
+            {flattened.map(exampleData => this.renderExample(exampleData))}
+          </tbody>
+        </table>
+      </div>
+    )
+  }
+}

frontend/components/category-headings.js

@@ -0,0 +1,32 @@
+import React from 'react'
+import PropTypes from 'prop-types'
+import { Link } from 'react-router-dom'
+
+const CategoryHeading = ({ category }) => {
+  const { id, name } = category
+
+  return (
+    <Link to={`/examples/${id}`}>
+      <h3 id={id}>{name}</h3>
+    </Link>
+  )
+}
+CategoryHeading.propTypes = {
+  category: PropTypes.shape({
+    id: PropTypes.string.isRequired,
+    name: PropTypes.string.isRequired,
+  }).isRequired,
+}
+
+const CategoryHeadings = ({ categories }) => (
+  <div>
+    {categories.map(category => (
+      <CategoryHeading category={category} key={category.id} />
+    ))}
+  </div>
+)
+CategoryHeadings.propTypes = {
+  categories: PropTypes.arrayOf(CategoryHeading.propTypes.category).isRequired,
+}
+
+export { CategoryHeading, CategoryHeadings }