From 6bbdec49bf84fb3b86c7c4e87555a1df584b8029 Mon Sep 17 00:00:00 2001
From: David Larlet <david@larlet.fr>
Date: Sat, 8 Jun 2024 09:16:56 -0400
Subject: [PATCH] chore: refactor web components with templates

---
 .../umap/js/components/alerts/alert.html      |  27 +++--
 .../static/umap/js/components/alerts/alert.js | 113 ++++++++----------
 umap/static/umap/js/components/base.js        |  54 +++++++++
 umap/static/umap/js/umap.layer.js             |   2 +-
 4 files changed, 119 insertions(+), 77 deletions(-)
 create mode 100644 umap/static/umap/js/components/base.js

diff --git a/umap/static/umap/js/components/alerts/alert.html b/umap/static/umap/js/components/alerts/alert.html
index cea8e628..553abb03 100644
--- a/umap/static/umap/js/components/alerts/alert.html
+++ b/umap/static/umap/js/components/alerts/alert.html
@@ -4,7 +4,7 @@
   @import "{% static 'umap/js/components/alerts/alert.css' %}";
 </style>
 
-<umap-alert hidden>
+<template id="umap-alert-template">
   <div role="dialog">
     <div>
       <p role="alert"></p>
@@ -13,9 +13,11 @@
       <i class="icon icon-16 icon-close"></i>
     </button>
   </div>
-</umap-alert>
+</template>
 
-<umap-alert-creation hidden>
+<umap-alert></umap-alert>
+
+<template id="umap-alert-creation-template">
   <div role="dialog">
     <div>
       <p role="alert"></p>
@@ -37,15 +39,17 @@
       <i class="icon icon-16 icon-close"></i>
     </button>
   </div>
-</umap-alert-creation>
+</template>
 
-<umap-alert-choice hidden>
+<umap-alert-creation></umap-alert-creation>
+
+<template id="umap-alert-choice-template">
   <div role="dialog">
     <div>
       <p role="alert"></p>
       <div id="choice-wrapper">
         <form>
-          <a href="" onclick="document.url" target="_blank">{% translate "See their edits in another tab" %}</a>
+          <a href="#" onclick="document.url" target="_blank">{% translate "See their edits in another tab" %}</a>
           <input id="your-changes" type="submit" value="{% translate "Keep your changes and loose theirs" %}">
           <input id="their-changes" type="submit" value="{% translate "Keep their changes and loose yours" %}">
         </form>
@@ -55,15 +59,18 @@
       <i class="icon icon-16 icon-close"></i>
     </button>
   </div>
-</umap-alert-choice>
+</template>
+
+<umap-alert-choice></umap-alert-choice>
 
 <script type="module">
+  import { register } from '{% static 'umap/js/components/base.js' %}'
   import {
     uMapAlert,
     uMapAlertCreation,
     uMapAlertChoice
   } from '{% static 'umap/js/components/alerts/alert.js' %}'
-  customElements.define('umap-alert', uMapAlert)
-  customElements.define('umap-alert-creation', uMapAlertCreation)
-  customElements.define('umap-alert-choice', uMapAlertChoice)
+  register(uMapAlert, 'umap-alert')
+  register(uMapAlertCreation, 'umap-alert-creation')
+  register(uMapAlertChoice, 'umap-alert-choice')
 </script>
diff --git a/umap/static/umap/js/components/alerts/alert.js b/umap/static/umap/js/components/alerts/alert.js
index 2769409d..3646944b 100644
--- a/umap/static/umap/js/components/alerts/alert.js
+++ b/umap/static/umap/js/components/alerts/alert.js
@@ -1,43 +1,57 @@
-class uMapAlert extends HTMLElement {
+import { uMapElement } from '../base.js'
+
+class uMapAlert extends uMapElement {
+  static get observedAttributes() {
+    return ['open']
+  }
+
+  attributeChangedCallback(name, oldValue, newValue) {
+    switch (name) {
+      case 'open':
+        newValue === 'open' ? this._show() : this._hide()
+        break
+    }
+  }
+
   static info(message, duration = 5000) {
-    const event = new CustomEvent('umap:alert', {
-      bubbles: true,
-      cancelable: true,
-      detail: { message, duration },
-    })
-    document.dispatchEvent(event)
+    uMapAlert.emit('alert', { message, duration })
   }
 
   // biome-ignore lint/style/useNumberNamespace: Number.Infinity returns undefined by default
   static error(message, duration = Infinity) {
-    const event = new CustomEvent('umap:alert', {
-      bubbles: true,
-      cancelable: true,
-      detail: { level: 'error', message, duration },
-    })
-    document.dispatchEvent(event)
+    uMapAlert.emit('alert', { level: 'error', message, duration })
   }
 
   constructor() {
     super()
+    this._hide()
     this.container = this.querySelector('[role="dialog"]')
     this.element = this.container.querySelector('[role="alert"]')
   }
 
   _hide() {
     this.setAttribute('hidden', 'hidden')
+    this.removeAttribute('open')
   }
 
   _show() {
     this.removeAttribute('hidden')
   }
 
-  _displayAlert(detail) {
-    const { level = 'info', duration = 5000, message = '' } = detail
+  _handleClose() {
+    this.addEventListener('click', (event) => {
+      if (event.target.closest('[data-close]')) {
+        this._hide()
+      }
+    })
+  }
+
+  onAlert(event) {
+    const { level = 'info', duration = 5000, message = '' } = event.detail
     this.container.dataset.level = level
     this.container.dataset.duration = duration
     this.element.textContent = message
-    this._show()
+    this.setAttribute('open', 'open')
     if (Number.isFinite(duration)) {
       setTimeout(() => {
         this._hide()
@@ -46,14 +60,8 @@ class uMapAlert extends HTMLElement {
   }
 
   connectedCallback() {
-    this.addEventListener('click', (event) => {
-      if (event.target.closest('[data-close]')) {
-        this._hide()
-      }
-    })
-    document.addEventListener('umap:alert', (event) => {
-      this._displayAlert(event.detail)
-    })
+    this._handleClose()
+    this.listen('alert')
   }
 }
 
@@ -65,12 +73,7 @@ class uMapAlertCreation extends uMapAlert {
     editLink = undefined,
     sendLink = undefined
   ) {
-    const event = new CustomEvent('umap:alert-creation', {
-      bubbles: true,
-      cancelable: true,
-      detail: { message, duration, editLink, sendLink },
-    })
-    document.dispatchEvent(event)
+    uMapAlertCreation.emit('alertCreation', { message, duration, editLink, sendLink })
   }
 
   constructor() {
@@ -79,15 +82,15 @@ class uMapAlertCreation extends uMapAlert {
     this.formWrapper = this.container.querySelector('#form-wrapper')
   }
 
-  _displayCreationAlert(detail) {
+  onAlertCreation(event) {
     const {
       level = 'info',
       duration = 5000,
       message = '',
       editLink = undefined,
       sendLink = undefined,
-    } = detail
-    uMapAlert.prototype._displayAlert.call(this, { level, duration, message })
+    } = event.detail
+    uMapAlert.prototype.onAlert.call(this, { detail: { level, duration, message } })
     this.linkWrapper.querySelector('input[type="url"]').value = editLink
     const button = this.linkWrapper.querySelector('input[type="button"]')
     button.addEventListener('click', (event) => {
@@ -102,21 +105,15 @@ class uMapAlertCreation extends uMapAlert {
         event.preventDefault()
         const formData = new FormData(form)
         const server = new U.ServerRequest()
-        this._hide()
+        this.removeAttribute('open')
         await server.post(sendLink, {}, formData)
       })
     }
   }
 
   connectedCallback() {
-    this.addEventListener('click', (event) => {
-      if (event.target.closest('[data-close]')) {
-        this._hide()
-      }
-    })
-    document.addEventListener('umap:alert-creation', (event) => {
-      this._displayCreationAlert(event.detail)
-    })
+    this._handleClose()
+    this.listen('alertCreation')
   }
 }
 
@@ -126,12 +123,7 @@ class uMapAlertChoice extends uMapAlert {
     // biome-ignore lint/style/useNumberNamespace: Number.Infinity returns undefined by default
     duration = Infinity
   ) {
-    const event = new CustomEvent('umap:alert-choice', {
-      bubbles: true,
-      cancelable: true,
-      detail: { level: 'error', message, duration },
-    })
-    document.dispatchEvent(event)
+    uMapAlertChoice.emit('alertChoice', { level: 'error', message, duration })
   }
 
   constructor() {
@@ -139,38 +131,27 @@ class uMapAlertChoice extends uMapAlert {
     this.choiceWrapper = this.container.querySelector('#choice-wrapper')
   }
 
-  _displayChoiceAlert(detail) {
-    const { level = 'info', duration = 5000, message = '' } = detail
-    uMapAlert.prototype._displayAlert.call(this, { level, duration, message })
+  onAlertChoice(event) {
+    const { level = 'info', duration = 5000, message = '' } = event.detail
+    uMapAlert.prototype.onAlert.call(this, { detail: { level, duration, message } })
     const form = this.choiceWrapper.querySelector('form')
     form.addEventListener('submit', (event) => {
       event.preventDefault()
       switch (event.submitter.id) {
         case 'your-changes':
-          document.dispatchEvent(
-            new CustomEvent('umap:alert-choice-override', {
-              bubbles: true,
-              cancelable: true,
-            })
-          )
+          uMapAlertChoice.emit('alertChoiceOverride')
           break
         case 'their-changes':
           window.location.reload()
           break
       }
-      this._hide()
+      this.removeAttribute('open')
     })
   }
 
   connectedCallback() {
-    this.addEventListener('click', (event) => {
-      if (event.target.closest('[data-close]')) {
-        this._hide()
-      }
-    })
-    document.addEventListener('umap:alert-choice', (event) => {
-      this._displayChoiceAlert(event.detail)
-    })
+    this._handleClose()
+    this.listen('alertChoice')
   }
 }
 
diff --git a/umap/static/umap/js/components/base.js b/umap/static/umap/js/components/base.js
new file mode 100644
index 00000000..f4247a22
--- /dev/null
+++ b/umap/static/umap/js/components/base.js
@@ -0,0 +1,54 @@
+export class uMapElement extends HTMLElement {
+  static EVENT_PREFIX = 'umap'
+
+  static emit(type, detail = {}) {
+    const event = new CustomEvent(`${uMapElement.EVENT_PREFIX}:${type}`, {
+      bubbles: true,
+      cancelable: true,
+      detail: detail,
+    })
+    return document.dispatchEvent(event)
+  }
+
+  /**
+   * Retrieves a clone of the content template either using the `template`
+   * attribute or an id mathing the name of the component:
+   *
+   * `umap-alert` component => `umap-alert-template` template id lookup.
+   */
+  get template() {
+    return document
+      .getElementById(this.getAttribute('template') || `${this.localName}-template`)
+      .content.cloneNode(true)
+  }
+
+  constructor() {
+    super()
+    this.append(this.template)
+  }
+
+  /**
+   * Special method which allows to easily listen to events
+   * and have automated event to component method binding.
+   *
+   * For instance listening to `alert` will then call `onAlert`.
+   */
+  handleEvent(event) {
+    event.preventDefault()
+    // From `umap:alert` to `alert`.
+    const eventName = event.type.replace(`${uMapElement.EVENT_PREFIX}:`, '')
+    // From `alert` event type to `onAlert` call against that class.
+    this[`on${eventName.charAt(0).toUpperCase() + eventName.slice(1)}`](event)
+  }
+
+  listen(eventName) {
+    // Using `this` as a listener will call `handleEvent` under the hood.
+    document.addEventListener(`${uMapElement.EVENT_PREFIX}:${eventName}`, this)
+  }
+}
+
+export function register(klass, name) {
+  if ('customElements' in globalThis && !customElements.get(name)) {
+    customElements.define(name, klass)
+  }
+}
diff --git a/umap/static/umap/js/umap.layer.js b/umap/static/umap/js/umap.layer.js
index 602ca0c7..432ba30a 100644
--- a/umap/static/umap/js/umap.layer.js
+++ b/umap/static/umap/js/umap.layer.js
@@ -1711,7 +1711,7 @@ U.DataLayer = L.Evented.extend({
               'This situation is tricky, you have to choose carefully which version is pertinent.'
           )
         )
-        document.addEventListener('umap:alert-choice-override', async (event) => {
+        document.addEventListener('alertChoiceOverride', async (event) => {
           await this._trySave(url, {}, formData)
         })
       }