email editor

app/javascript/application.js

@@ -37,6 +37,7 @@ import AppTour from './elements/app_tour'
 import DashboardDropzone from './elements/dashboard_dropzone'
 import RequiredCheckboxGroup from './elements/required_checkbox_group'
 import PageContainer from './elements/page_container'
+import EmailEditor from './elements/email_editor'
 
 import * as TurboInstantClick from './lib/turbo_instant_click'
 
@@ -109,6 +110,7 @@ safeRegisterElement('dashboard-dropzone', DashboardDropzone)
 safeRegisterElement('check-on-click', CheckOnClick)
 safeRegisterElement('required-checkbox-group', RequiredCheckboxGroup)
 safeRegisterElement('page-container', PageContainer)
+safeRegisterElement('email-editor', EmailEditor)
 
 safeRegisterElement('template-builder', class extends HTMLElement {
   connectedCallback () {

app/javascript/elements/email_editor.js

@@ -0,0 +1,131 @@
+import { target, targetable } from '@github/catalyst/lib/targetable'
+
+let loaderPromise = null
+
+function loadCodeMirror () {
+  if (!loaderPromise) {
+    loaderPromise = Promise.all([
+      import(/* webpackChunkName: "email-editor" */ '@codemirror/view'),
+      import(/* webpackChunkName: "email-editor" */ '@codemirror/commands'),
+      import(/* webpackChunkName: "email-editor" */ '@codemirror/language'),
+      import(/* webpackChunkName: "email-editor" */ '@codemirror/lang-html'),
+      import(/* webpackChunkName: "email-editor" */ '@specious/htmlflow')
+    ]).then(([view, commands, language, html, htmlflow]) => {
+      return {
+        minimalSetup: [
+          commands.history(),
+          language.syntaxHighlighting(language.defaultHighlightStyle, { fallback: true }),
+          view.keymap.of([...commands.defaultKeymap, ...commands.historyKeymap])
+        ],
+        EditorView: view.EditorView,
+        html: html.html,
+        htmlflow: htmlflow.default || htmlflow
+      }
+    })
+  }
+
+  return loaderPromise
+}
+
+export default targetable(class extends HTMLElement {
+  static [target.static] = [
+    'codeViewTab',
+    'previewViewTab',
+    'editorContainer',
+    'previewIframe'
+  ]
+
+  connectedCallback () {
+    this.mount()
+
+    if (this.input.value) {
+      this.showPreviewView()
+    } else {
+      this.showCodeView()
+    }
+
+    this.previewViewTab.addEventListener('click', this.showPreviewView)
+    this.codeViewTab.addEventListener('click', this.showCodeView)
+  }
+
+  showCodeView = () => {
+    this.editorView.dispatch({
+      changes: { from: 0, to: this.editorView.state.doc.length, insert: this.input.value }
+    })
+
+    this.previewViewTab.classList.remove('tab-active', 'tab-bordered')
+    this.previewViewTab.classList.add('pb-[3px]')
+    this.codeViewTab.classList.remove('pb-[3px]')
+    this.codeViewTab.classList.add('tab-active', 'tab-bordered')
+    this.editorContainer.classList.remove('hidden')
+    this.previewIframe.classList.add('hidden')
+  }
+
+  showPreviewView = () => {
+    this.previewIframe.srcdoc = this.input.value
+
+    this.codeViewTab.classList.remove('tab-active', 'tab-bordered')
+    this.codeViewTab.classList.add('pb-[3px]')
+    this.previewViewTab.classList.remove('pb-[3px]')
+    this.previewViewTab.classList.add('tab-active', 'tab-bordered')
+    this.editorContainer.classList.add('hidden')
+    this.previewIframe.classList.remove('hidden')
+  }
+
+  async mount () {
+    this.input = this.querySelector('input[type="hidden"]')
+    this.input.style.display = 'none'
+
+    const { EditorView, minimalSetup, html, htmlflow } = await loadCodeMirror()
+
+    this.editorView = new EditorView({
+      doc: this.input.value,
+      parent: this.editorContainer,
+      extensions: [
+        html(),
+        minimalSetup,
+        EditorView.lineWrapping,
+        EditorView.updateListener.of(update => {
+          if (update.docChanged) this.input.value = update.state.doc.toString()
+        }),
+        EditorView.theme({
+          '&': {
+            backgroundColor: 'white',
+            color: 'black',
+            fontSize: '14px',
+            fontFamily: 'monospace'
+          },
+          '&.cm-focused': {
+            outline: 'none'
+          },
+          '&.cm-editor': {
+            borderRadius: '0.375rem',
+            border: 'none'
+          },
+          '.cm-gutters': {
+            display: 'none'
+          }
+        })
+      ]
+    })
+
+    this.previewIframe.srcdoc = this.editorView.state.doc.toString()
+
+    this.previewIframe.onload = () => {
+      const previewIframeDoc = this.previewIframe.contentDocument
+
+      if (previewIframeDoc.body) {
+        previewIframeDoc.body.contentEditable = true
+      }
+
+      const contentDocument = this.previewIframe.contentDocument || this.previewIframe.contentWindow.document
+
+      contentDocument.body.addEventListener('input', async () => {
+        const html = contentDocument.documentElement.outerHTML.replace(' contenteditable="true"', '')
+        const prettifiedHtml = await htmlflow(html)
+
+        this.input.value = prettifiedHtml
+      })
+    }
+  }
+})