allow customizing the element that Drive replaces

While most of the time, replacing `<body>` makes perfect sense, when working with 3rd party integrations (i.e. Stripe), there are elements injected just before the closing `</body>` tag that should not be removed between page visits. There is more detail on this issue, particularly with injected `<iframe>` elements in hotwired#305 (comment). Now, if someone wants to customize the element that is replaced by Drive, they can add `data-turbo-drive-body` to an element, and only that element will be replaced between visits.
agrobbin · Jul 19, 2022 · 0e5191d · 0e5191d
1 parent 975054b
commit 0e5191d
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Showing 5 changed files with 90 additions and 3 deletions.
diff --git a/src/core/drive/page_renderer.ts b/src/core/drive/page_renderer.ts
@@ -1,18 +1,26 @@
 import { Renderer } from "../renderer"
 import { PageSnapshot } from "./page_snapshot"
 import { ReloadReason } from "../native/browser_adapter"
+import { nextEventLoopTick, getBodyElementId } from "../../util"
 
 export class PageRenderer extends Renderer<HTMLBodyElement, PageSnapshot> {
-  static renderElement(currentElement: HTMLBodyElement, newElement: HTMLBodyElement) {
+  static async renderElement(currentElement: HTMLBodyElement, newElement: HTMLBodyElement) {
+    await nextEventLoopTick()
+
     if (document.body && newElement instanceof HTMLBodyElement) {
-      document.body.replaceWith(newElement)
+      const bodyElementId = getBodyElementId()
+
+      const currentBody = (bodyElementId && document.querySelector(`#${bodyElementId}`)) || document.body
+      const newBody = (bodyElementId && newElement.querySelector(`#${bodyElementId}`)) || newElement
+
+      currentBody.replaceWith(newBody)
     } else {
       document.documentElement.appendChild(newElement)
     }
   }
 
   get shouldRender() {
-    return this.newSnapshot.isVisitable && this.trackedElementsAreIdentical
+    return this.newSnapshot.isVisitable && this.trackedElementsAreIdentical && this.bodyElementMatches
   }
 
   get reloadReason(): ReloadReason {
@@ -27,6 +35,12 @@ export class PageRenderer extends Renderer<HTMLBodyElement, PageSnapshot> {
         reason: "tracked_element_mismatch",
       }
     }
+
+    if (!this.bodyElementMatches) {
+      return {
+        reason: "body_element_mismatch",
+      }
+    }
   }
 
   prepareToRender() {
@@ -76,6 +90,12 @@ export class PageRenderer extends Renderer<HTMLBodyElement, PageSnapshot> {
     return this.currentHeadSnapshot.trackedElementSignature == this.newHeadSnapshot.trackedElementSignature
   }
 
+  get bodyElementMatches() {
+    const elementId = getBodyElementId()
+
+    return !elementId || this.newElement.querySelector(`#${elementId}`) !== null
+  }
+
   copyNewHeadStylesheetElements() {
     for (const element of this.newHeadStylesheetElements) {
       document.head.appendChild(element)

diff --git a/src/tests/fixtures/drive_custom_body.html b/src/tests/fixtures/drive_custom_body.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta name="turbo-body" content="app">
+    <title>Drive (with custom body)</title>
+    <script src="/dist/turbo.es2017-umd.js" data-turbo-track="reload"></script>
+    <script src="/src/tests/fixtures/test.js"></script>
+  </head>
+  <body>
+    <h1>Drive (with custom body)</h1>
+
+    <div id="app">
+      <div>
+        <a id="drive" href="/src/tests/fixtures/drive_custom_body_2.html">Drive enabled link</a>
+      </div>
+
+      <p id="different-content">Drive 1</p>
+    </div>
+  </body>
+</html>
diff --git a/src/tests/fixtures/drive_custom_body_2.html b/src/tests/fixtures/drive_custom_body_2.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta name="turbo-body" content="app">
+    <title>Drive (with custom body)</title>
+    <script src="/dist/turbo.es2017-umd.js" data-turbo-track="reload"></script>
+    <script src="/src/tests/fixtures/test.js"></script>
+  </head>
+  <body>
+    <h1>Drive (with custom body 2)</h1>
+
+    <div id="app">
+      <div>
+        <a id="drive" href="/src/tests/fixtures/drive_custom_body.html">Drive enabled link</a>
+      </div>
+
+      <p id="different-content">Drive 2</p>
+    </div>
+  </body>
+</html>
diff --git a/src/tests/functional/drive_custom_body_tests.ts b/src/tests/functional/drive_custom_body_tests.ts
@@ -0,0 +1,21 @@
+import { test } from "@playwright/test"
+import { assert } from "chai"
+import { nextBody, pathname } from "../helpers/page"
+
+const path = "/src/tests/fixtures/drive_custom_body.html"
+
+test.beforeEach(async ({ page }) => {
+  await page.goto(path)
+})
+
+test("test drive with a custom body element", async ({ page }) => {
+  page.click("#drive")
+  await nextBody(page)
+
+  const h1 = await page.locator("h1")
+  const differentContent = await page.locator("#different-content")
+
+  assert.equal(pathname(page.url()), "/src/tests/fixtures/drive_custom_body_2.html")
+  assert.equal(await h1.textContent(), "Drive (with custom body)")
+  assert.equal(await differentContent.textContent(), "Drive 2")
+})
diff --git a/src/util.ts b/src/util.ts
@@ -96,6 +96,10 @@ export function clearBusyState(...elements: Element[]) {
   }
 }
 
+export function getBodyElementId(): string | null {
+  return getMetaContent("turbo-body")
+}
+
 export function getMetaElement(name: string): HTMLMetaElement | null {
   return document.querySelector(`meta[name="${name}"]`)
 }