hotwired · jorgemanrubia · Mar 14, 2024 · Feb 15, 2024 · Feb 15, 2024 · Feb 20, 2024
diff --git a/src/core/streams/actions/morph.js b/src/core/streams/actions/morph.js
@@ -0,0 +1,63 @@
+import { Idiomorph } from "idiomorph/dist/idiomorph.esm"
+import { dispatch } from "../../../util"
+
+export default function morph(streamElement) {
+  const morphStyle = streamElement.hasAttribute("children-only") ? "innerHTML" : "outerHTML"
+  streamElement.targetElements.forEach((element) => {
+    Idiomorph.morph(element, streamElement.templateContent, {
+      morphStyle: morphStyle,
+      callbacks: {
+        beforeNodeAdded,
+        beforeNodeMorphed,
+        beforeAttributeUpdated,
+        beforeNodeRemoved,
+        afterNodeMorphed
+      }
+    })
+  })
+}
+
+function beforeNodeAdded(node) {
+  return !(node.id && node.hasAttribute("data-turbo-permanent") && document.getElementById(node.id))
+}
+
+function beforeNodeRemoved(node) {
+  return beforeNodeAdded(node)
+}
+
+function beforeNodeMorphed(target, newElement) {
+  if (target instanceof HTMLElement && !target.hasAttribute("data-turbo-permanent")) {
+    const event = dispatch("turbo:before-morph-element", {
+      cancelable: true,
+      target,
+      detail: {
+        newElement
+      }
+    })
+    return !event.defaultPrevented
+  }
+  return false
+}
+
+function beforeAttributeUpdated(attributeName, target, mutationType) {
+  const event = dispatch("turbo:before-morph-attribute", {
+    cancelable: true,
+    target,
+    detail: {
+      attributeName,
+      mutationType
+    }
+  })
+  return !event.defaultPrevented
+}
+
+function afterNodeMorphed(target, newElement) {
+  if (newElement instanceof HTMLElement) {
+    dispatch("turbo:morph-element", {
+      target,
+      detail: {
+        newElement
+      }
+    })
+  }
+}
diff --git a/src/core/streams/stream_actions.js b/src/core/streams/stream_actions.js
@@ -1,4 +1,5 @@
 import { session } from "../"
+import morph from "./actions/morph"
 
 export const StreamActions = {
   after() {
@@ -36,5 +37,9 @@ export const StreamActions = {
 
   refresh() {
     session.refresh(this.baseURI, this.requestId)
+  },
+
+  morph() {
+    morph(this)
   }
 }
diff --git a/src/tests/fixtures/morph_stream_action.html b/src/tests/fixtures/morph_stream_action.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html id="html">
+  <head>
+    <meta charset="utf-8">
+    <title>Morph Stream Action</title>
+    <script src="/dist/turbo.es2017-umd.js" data-turbo-track="reload"></script>
+    <script src="/src/tests/fixtures/test.js"></script>
+    <meta name="turbo-refresh-method" content="replace">
+  </head>
+
+  <body>
+    <div id="message_1">
+      <div>Morph me</div>
+    </div>
+  </body>
+</html>
diff --git a/src/tests/functional/morph_stream_action_tests.js b/src/tests/functional/morph_stream_action_tests.js
@@ -0,0 +1,48 @@
+import { test, expect } from "@playwright/test"
+import { nextEventOnTarget, noNextEventOnTarget } from "../helpers/page"
+
+test("dispatches a turbo:before-morph-element & turbo:morph-element for each morph stream action", async ({ page }) => {
+  await page.goto("/src/tests/fixtures/morph_stream_action.html")
+
+  await page.evaluate(() => {
+    window.Turbo.renderStreamMessage(`
+      <turbo-stream action="morph" target="message_1">
+        <template>
+          <div id="message_1">
+            <h1>Morphed</h1>
+          </div>
+        </template>
+      </turbo-stream>
+    `)
+  })
+
+  await nextEventOnTarget(page, "message_1", "turbo:before-morph-element")
+  await nextEventOnTarget(page, "message_1", "turbo:morph-element")
+  await expect(page.locator("#message_1")).toHaveText("Morphed")
+})
+
+test("preventing a turbo:before-morph-element prevents the morph", async ({ page }) => {
+  await page.goto("/src/tests/fixtures/morph_stream_action.html")
+
+  await page.evaluate(() => {
+    addEventListener("turbo:before-morph-element", (event) => {
+      event.preventDefault()
+    })
+  })
+
+  await page.evaluate(() => {
+    window.Turbo.renderStreamMessage(`
+      <turbo-stream action="morph" target="message_1">
+        <template>
+          <div id="message_1">
+            <h1>Morphed</h1>
+          </div>
+        </template>
+      </turbo-stream>
+    `)
+  })
+
+  await nextEventOnTarget(page, "message_1", "turbo:before-morph-element")
+  await noNextEventOnTarget(page, "message_1", "turbo:morph-element")
+  await expect(page.locator("#message_1")).toHaveText("Morph me")
+})
diff --git a/src/tests/unit/stream_element_tests.js b/src/tests/unit/stream_element_tests.js
@@ -196,3 +196,32 @@ test("test action=refresh discarded when matching request id", async () => {
 
   assert.ok(document.body.hasAttribute("data-modified"))
 })
+
+test("action=morph", async () => {
+  const templateElement = createTemplateElement(`<h1 id="hello">Hello Turbo Morphed</h1>`)
+  const element = createStreamElement("morph", "hello", templateElement)
+
+  assert.equal(subject.find("div#hello")?.textContent, "Hello Turbo")
+
+  subject.append(element)
+  await nextAnimationFrame()
+
+  assert.notOk(subject.find("div#hello"))
+  assert.equal(subject.find("h1#hello")?.textContent, "Hello Turbo Morphed")
+})
+
+test("action=morph children-only", async () => {
+  const templateElement = createTemplateElement(`<h1 id="hello-child-element">Hello Turbo Morphed</h1>`)
+  const element = createStreamElement("morph", "hello", templateElement)
+  const target = subject.find("div#hello")
+  assert.equal(target?.textContent, "Hello Turbo")
+  element.setAttribute("children-only", true)
+
+  subject.append(element)
+
+  await nextAnimationFrame()
+
+  assert.ok(subject.find("div#hello"))
+  assert.ok(subject.find("div#hello > h1#hello-child-element"))
+  assert.equal(subject.find("div#hello > h1#hello-child-element").textContent, "Hello Turbo Morphed")
+})