Adding semi-functional rendering demo of app

package.json

@@ -71,6 +71,7 @@
   },
   "dependencies": {
     "@babel/core": "^7.2.2",
+    "@ungap/url-search-params": "^0.1.2",
     "babel-core": "^7.0.0-bridge.0",
     "babel-jest": "^23.6.0",
     "babel-preset-gatsby": "^0.1.6",

src/components/App/context.js

@@ -0,0 +1,5 @@
+import React from 'react';
+
+const AppContext = React.createContext();
+
+export default AppContext;

src/components/App/index.js

@@ -0,0 +1,161 @@
+import React from 'react';
+import URLSearchParams from '@ungap/url-search-params';
+
+import AppContext from 'components/App/context';
+import Form from 'components/Form';
+import Loader from 'components/Loader';
+import Message from 'components/Message';
+import SVG from 'components/SVG';
+
+const toUrl = params => new URLSearchParams(params).toString();
+
+const readURLHash = () => {
+  const query = document.location.hash.slice(1);
+  const params = new URLSearchParams(query);
+
+  if (params.get('syntax')) {
+    return {
+      syntax: params.get('syntax'),
+      expr: params.get('expr')
+    };
+  } else {
+    // Assuming old-style URL
+    return {
+      syntax: 'js',
+      expr: query || ''
+    };
+  }
+};
+
+const createSvgLink = async ({ svg }) => {
+  try {
+    const type = 'image/svg+xml';
+    const blob = new Blob([svg], { type });
+
+    return {
+      url: URL.createObjectURL(blob),
+      label: 'Download SVG',
+      filename: 'image.svg',
+      type
+    };
+  }
+  catch (e) {
+    console.error(e); // eslint-disable-line no-console
+  }
+};
+
+const createPngLink = async ({ svg, width, height }) => {
+  try {
+    const type = 'image/png';
+    const canvas = document.createElement('canvas');
+    const context = canvas.getContext('2d');
+    const loader = new Image();
+
+    loader.width = canvas.width = Number(width) * 2;
+    loader.height = canvas.height = Number(height) * 2;
+
+    await new Promise(resolve => {
+      loader.onload = resolve;
+      loader.src = 'data:image/svg+xml,' + encodeURIComponent(svg);
+    });
+
+    context.drawImage(loader, 0, 0, loader.width, loader.height);
+
+    const blob = await new Promise(resolve => canvas.toBlob(resolve, type));
+
+    return {
+      url: URL.createObjectURL(blob),
+      label: 'Download PNG',
+      filename: 'image.png',
+      type
+    };
+  }
+  catch (e) {
+    console.error(e); // eslint-disable-line no-console
+  }
+};
+
+class App extends React.PureComponent {
+  state={
+    ...readURLHash()
+  }
+
+  componentDidMount() {
+    window.addEventListener('hashchange', this.handleHashChange);
+    this.handleHashChange();
+  }
+
+  componentWillUnmount() {
+    window.removeEventListener('hashchange', this.handleHashChange);
+  }
+
+  handleHashChange = () => {
+    const { expr, syntax } = readURLHash();
+
+    if (!expr) {
+      return;
+    }
+
+    this.setState({
+      syntax,
+      expr,
+      permalinkUrl: document.location.toString()
+    });
+    console.log('Render:', syntax, expr); // eslint-disable-line no-console
+  }
+
+  handleRetry = event => {
+    event.preventDefault();
+    this.handleHashChange();
+  }
+
+  renderExpr = ({ expr, syntax }) => {
+    if (expr) {
+      document.location.hash = toUrl({ syntax, expr });
+    }
+  }
+
+  svgData = async ({ svg, width, height }) => {
+    if (svg !== this.state.svg) {
+      this.setState({
+        svg,
+        svgLink: await createSvgLink({ svg }),
+        pngLink: await createPngLink({ svg, width, height })
+      });
+    }
+  }
+
+  render() {
+    const {
+      svgLink,
+      pngLink,
+      permalinkUrl,
+      expr,
+      syntax
+    } = this.state;
+    const context = {
+      svgLink,
+      pngLink,
+      permalinkUrl,
+      expr,
+      syntax,
+      renderExpr: this.renderExpr,
+      svgData: this.svgData
+    };
+
+    return <AppContext.Provider value={ context }>
+      <Form />
+
+      <Loader />
+
+      <Message type="error" heading="Render Failure">
+        <p>An error occurred while rendering the regular expression.</p>
+        <a href="#retry" onClick={ this.handleRetry }>Retry</a>
+      </Message>
+
+      <SVG />
+    </AppContext.Provider>;
+  }
+}
+
+export default App;

src/components/Form/index.js

@@ -0,0 +1,71 @@
+import React from 'react';
+
+import ExpandIcon from 'react-feather/dist/icons/chevrons-down';
+
+import style from './style.module.css';
+
+import AppContext from 'components/App/context';
+import FormActions from 'components/FormActions';
+
+const syntaxList = [
+  { id: 'js', label: 'JavaScript' },
+  { id: 'pcre', label: 'PCRE' }
+];
+
+class Form extends React.PureComponent {
+  static contextType = AppContext
+
+  state = {
+    expr: this.context.expr,
+    syntax: this.context.syntax
+  }
+
+  handleSubmit = event => {
+    event.preventDefault();
+
+    const { expr, syntax } = this.state;
+
+    this.context.renderExpr({ expr, syntax });
+  }
+
+  handleKeyPress = event => {
+    if (event.charCode === 13 && event.shiftKey) {
+      this.handleSubmit(event);
+    }
+  }
+
+  handleChange = event => this.setState({
+    [event.target.name]: event.target.value
+  })
+
+  render() {
+    const { expr, syntax } = this.state;
+
+    return <div className={ style.form }>
+      <form onSubmit={ this.handleSubmit }>
+        <textarea
+          name="expr"
+          value={ expr }
+          onKeyPress={ this.handleKeyPress }
+          onChange={ this.handleChange }
+          autoFocus
+          placeholder="Enter regular expression to display"></textarea>
+        <button type="submit">Display</button>
+        <div className={ style.select }>
+          <select
+            name="syntax"
+            value={ syntax }
+            onChange={ this.handleChange } >
+            { syntaxList.map(({ id, label }) => (
+              <option value={ id } key={ id }>{ label }</option>
+            )) }
+          </select>
+          <ExpandIcon />
+        </div>
+        <FormActions />
+      </form>
+    </div>;
+  }
+}
+
+export default Form;

src/components/Form/style.module.css

@@ -0,0 +1,49 @@
+@import url('../../globals.module.css');
+
+:root {
+  --control-gradient: var(--color-green) var(--gradient-green);
+  --select-height: 2.8rem;
+  --select-width: 12rem;
+  --entry-line-height: 1.5em;
+}
+
+.form {
+  margin: var(--spacing-margin) 0;
+  overflow: hidden; /* Keep floated content in the box */
+
+  & textarea {
+    display: block;
+    font-size: inherit;
+    line-height: var(--entry-line-height);
+    border: 0 none;
+    outline: none;
+    background: var(--color-tan);
+    padding: 0 1rem;
+    margin-bottom: var(--spacing-margin);
+    width: 100% !important; /* "!important" to prevent user changing width */
+    height: calc(3 * var(--entry-line-height));
+    box-sizing: border-box;
+    font-family: Consolas, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace;
+  }
+
+  & textarea::placeholder {
+    color: var(--color-brown);
+  }
+
+  & button {
+    font-size: inherit;
+    font-weight: bold;
+    line-height: 2.8rem;
+    width: 10rem;
+    border: 0 none;
+    background: var(--control-gradient);
+    color: var(--color-black);
+    cursor: pointer;
+    padding: 0;
+    margin-right: 1rem;
+  }
+}
+
+.select {
+  composes: fancy-select;
+}

src/components/FormActions/index.js

@@ -0,0 +1,38 @@
+import React from 'react';
+
+import DownloadIcon from 'react-feather/dist/icons/download';
+import LinkIcon from 'react-feather/dist/icons/link';
+
+import style from './style.module.css';
+
+import AppContext from 'components/App/context';
+
+class FormActions extends React.PureComponent {
+  static contextType = AppContext
+
+  downloadLink({ url, filename, type, label }) {
+    return <li>
+      <a href={ url } download={ filename } type={ type }>
+        <DownloadIcon />{ label }
+      </a>
+    </li>;
+  }
+
+  render() {
+    const {
+      permalinkUrl,
+      svgLink,
+      pngLink
+    } = this.context;
+
+    return <ul className={ style.actions }>
+      { pngLink && this.downloadLink(pngLink) }
+      { svgLink && this.downloadLink(svgLink) }
+      { permalinkUrl && <li>
+        <a href={ permalinkUrl }><LinkIcon />Permalink</a>
+      </li> }
+    </ul>;
+  }
+}
+
+export default FormActions;

src/components/FormActions/style.module.css

@@ -0,0 +1,19 @@
+@import url('../../globals.module.css');
+
+.actions {
+  composes: inline-list with-separator-left;
+  float: right;
+
+  @media (max-width: 700px) {
+    & li {
+      display: block;
+    }
+  }
+
+  & svg {
+    width: 1em;
+    height: 1em;
+    margin-right: 0.5rem;
+    vertical-align: middle;
+  }
+}

src/components/Loader/__snapshots__/test.js.snap

@@ -0,0 +1,80 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Loader rendering 1`] = `
+<Loader>
+  <div
+    className="loader"
+  >
+    <Loader
+      color="currentColor"
+      size="24"
+    >
+      <svg
+        fill="none"
+        height="24"
+        stroke="currentColor"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+        strokeWidth="2"
+        viewBox="0 0 24 24"
+        width="24"
+        xmlns="http://www.w3.org/2000/svg"
+      >
+        <line
+          x1="12"
+          x2="12"
+          y1="2"
+          y2="6"
+        />
+        <line
+          x1="12"
+          x2="12"
+          y1="18"
+          y2="22"
+        />
+        <line
+          x1="4.93"
+          x2="7.76"
+          y1="4.93"
+          y2="7.76"
+        />
+        <line
+          x1="16.24"
+          x2="19.07"
+          y1="16.24"
+          y2="19.07"
+        />
+        <line
+          x1="2"
+          x2="6"
+          y1="12"
+          y2="12"
+        />
+        <line
+          x1="18"
+          x2="22"
+          y1="12"
+          y2="12"
+        />
+        <line
+          x1="4.93"
+          x2="7.76"
+          y1="19.07"
+          y2="16.24"
+        />
+        <line
+          x1="16.24"
+          x2="19.07"
+          y1="7.76"
+          y2="4.93"
+        />
+      </svg>
+    </Loader>
+    <div
+      className="message"
+    >
+      Loading...
+    </div>
+  </div>
+</Loader>
+`;

src/components/Loader/index.js

@@ -0,0 +1,14 @@
+import React from 'react';
+
+import LoaderIcon from 'react-feather/dist/icons/loader';
+
+import style from './style.module.css';
+
+const Loader = () => (
+  <div className={ style.loader }>
+    <LoaderIcon />
+    <div className={ style.message }>Loading...</div>
+  </div>
+);
+
+export default Loader;

src/components/Loader/style.module.css

@@ -0,0 +1,43 @@
+@import url('../../globals.module.css');
+
+.loader {
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+  margin: var(--spacing-margin) 0;
+  padding: 2rem;
+  background: var(--color-white);
+  color: var(--color-black);
+
+  & .message {
+    font-weight: bold;
+    font-size: 2.5rem;
+    margin-top: 2rem;
+    padding: 0;
+    text-align: center;
+  }
+
+  & svg {
+    display: block;
+    transform: scaleZ(1); /* Move to separate render layer in Chrome */
+    width: 4rem;
+    height: 4rem;
+    stroke: var(--color-black);
+    animation: loader-spin 1s steps(8) infinite;
+
+    & line:nth-of-type(1) { stroke: color(var(--color-black) alpha(0.75)); }
+    & line:nth-of-type(3) { stroke: color(var(--color-black) alpha(0.50)); }
+    & line:nth-of-type(5) { stroke: color(var(--color-black) alpha(0.25)); }
+    & line:nth-of-type(7) { stroke: color(var(--color-black) alpha(0)); }
+  }
+}
+
+@keyframes loader-spin {
+  from {
+    transform: rotate(0deg);
+  }
+  to {
+    transform: rotate(360deg);
+  }
+}

src/components/Loader/test.js

@@ -0,0 +1,15 @@
+import React from 'react';
+import { mount } from 'enzyme';
+
+import Loader from 'components/Loader';
+
+describe('Loader', () => {
+  test('rendering', () => {
+    // Using full rendering here since styles for this depend on the structure
+    // of the SVG.
+    const component = mount(
+      <Loader />
+    );
+    expect(component).toMatchSnapshot();
+  });
+});

src/components/SVG/index.js

@@ -0,0 +1,43 @@
+import React from 'react';
+
+import PlaceholderIcon from 'react-feather/dist/icons/file-text';
+
+import style from './style.module.css';
+
+import AppContext from 'components/App/context';
+
+class SVG extends React.PureComponent {
+  static contextType = AppContext
+
+  svgContainer = React.createRef()
+
+  provideSVGData() {
+    if (!this.svgContainer.current) {
+      return;
+    }
+
+    const svg = this.svgContainer.current.querySelector('svg');
+    this.context.svgData({
+      svg: svg.outerHTML,
+      width: svg.getAttribute('width'),
+      height: svg.getAttribute('height')
+    });
+  }
+
+  componentDidMount() {
+    this.provideSVGData();
+  }
+
+  componentDidUpdate() {
+    this.provideSVGData();
+  }
+
+  render() {
+    // Demo rendering for now
+    return <div className={ style.render } ref={ this.svgContainer }>
+      <PlaceholderIcon />
+    </div>;
+  }
+}
+
+export default SVG;

src/components/SVG/style.module.css

@@ -0,0 +1,15 @@
+@import url('../../globals.module.css');
+
+.render {
+  width: 100%;
+  background: var(--color-white);
+  box-sizing: border-box;
+  overflow: auto;
+  margin: var(--spacing-margin) 0;
+
+  & svg {
+    display: block;
+    transform: scaleZ(1); /* Move to separate render layer in Chrome */
+    margin: 0 auto;
+  }
+}

src/pages/__snapshots__/index.test.js.snap

@@ -22,10 +22,6 @@ exports[`Index Page rendering 1`] = `
       </p>
     </Message>
   </noscript>
-  <div>
-    <WithMergedOptions(TransComponent)>
-      Hello world
-    </WithMergedOptions(TransComponent)>
-  </div>
+  <App />
 </Fragment>
 `;

src/pages/index.js

@@ -1,9 +1,9 @@
 import React from 'react';
 import { Link } from 'gatsby';
-import { withNamespaces, Trans } from 'react-i18next';
 
 import Metadata from 'components/Metadata';
 import Message from 'components/Message';
+import App from 'components/App';
 
 export const IndexPage = () => <>
   <Metadata/>
@@ -14,7 +14,7 @@ export const IndexPage = () => <>
         please see the <Link to="/privacy">Privacy Policy</Link>.</p>
     </Message>
   </noscript>
-  <div><Trans>Hello world</Trans></div>
+  <App />
 </>;
 
-export default withNamespaces()(IndexPage);
+export default IndexPage;

yarn.lock

@@ -940,6 +940,11 @@
   resolved "https://registry.yarnpkg.com/@types/tmp/-/tmp-0.0.32.tgz#0d3cb31022f8427ea58c008af32b80da126ca4e3"
   integrity sha1-DTyzECL4Qn6ljACK8yuA2hJspOM=
 
+"@ungap/url-search-params@^0.1.2":
+  version "0.1.2"
+  resolved "https://registry.yarnpkg.com/@ungap/url-search-params/-/url-search-params-0.1.2.tgz#8ba8c0527543fe675d1c29ae0a2daca842e8ee4f"
+  integrity sha512-WVk5+lJ+AoNLh2sIDMhnEAgLsVQuI067hWLJCzirErH1GYiy1gs09q4+XZxYWSvdAsslKsaO4q1iXXMx2c72dA==
+
 "@webassemblyjs/ast@1.7.11":
   version "1.7.11"
   resolved "https://registry.yarnpkg.com/@webassemblyjs/ast/-/ast-1.7.11.tgz#b988582cafbb2b095e8b556526f30c90d057cace"