⚡️ cache for loadMicroApp (#986)

.eslintrc.js

@@ -14,4 +14,9 @@ module.exports = {
     'no-underscore-dangle': 0,
     'no-plusplus': 0,
   },
+  parserOptions: {
+    tsconfigRootDir: __dirname,
+    project: './tsconfig.json',
+    createDefaultProgram: true,
+  },
 };

examples/main/multiple.js

@@ -9,6 +9,15 @@ const app1 = loadMicroApp(
   },
 );
 
+// for cached scenario
+setTimeout(() => {
+  app1.unmount();
+
+  setTimeout(() => {
+    loadMicroApp({ name: 'react15', entry: '//localhost:7102', container: '#react15' });
+  }, 1000 * 5);
+}, 1000 * 5);
+
 const app2 = loadMicroApp(
   { name: 'vue', entry: '//localhost:7101', container: '#vue' },
   {

src/__tests__/utils.test.ts

@@ -1,4 +1,11 @@
-import { getWrapperId, getDefaultTplWrapper, validateExportLifecycle, sleep, Deferred } from '../utils';
+import {
+  Deferred,
+  getDefaultTplWrapper,
+  getWrapperId,
+  getXPathForElement,
+  sleep,
+  validateExportLifecycle,
+} from '../utils';
 
 test('should wrap the id [1]', () => {
   const id = 'REACT16';
@@ -86,3 +93,22 @@ test('Deferred should worked [2]', async () => {
 
   expect(err).toBeInstanceOf(Error);
 });
+
+test('should getXPathForElement work well', () => {
+  const article = document.createElement('article');
+  article.innerHTML = `
+    <div>
+      <div></div>
+      <div id="testNode"></div>
+      <div></div>
+    </div>
+  `;
+
+  document.body.appendChild(article);
+  const testNode = document.querySelector('#testNode');
+  const xpath = getXPathForElement(testNode!, document);
+  expect(xpath).toEqual(
+    // eslint-disable-next-line max-len
+    `/*[name()='HTML' and namespace-uri()='http://www.w3.org/1999/xhtml']/*[name()='BODY' and namespace-uri()='http://www.w3.org/1999/xhtml'][1]/*[name()='ARTICLE' and namespace-uri()='http://www.w3.org/1999/xhtml'][1]/*[name()='DIV' and namespace-uri()='http://www.w3.org/1999/xhtml'][1]/*[name()='DIV' and namespace-uri()='http://www.w3.org/1999/xhtml'][2]`,
+  );
+});

src/apis.ts

@@ -1,9 +1,9 @@
 import { noop } from 'lodash';
-import { mountRootParcel, registerApplication, start as startSingleSpa } from 'single-spa';
+import { mountRootParcel, ParcelConfigObject, registerApplication, start as startSingleSpa } from 'single-spa';
 import { FrameworkConfiguration, FrameworkLifeCycles, LoadableApp, MicroApp, RegistrableApp } from './interfaces';
 import { loadApp } from './loader';
 import { doPrefetchStrategy } from './prefetch';
-import { Deferred, toArray } from './utils';
+import { Deferred, getXPathForElement, toArray } from './utils';
 
 let microApps: RegistrableApp[] = [];
 
@@ -46,16 +46,55 @@ export function registerMicroApps<T extends object = {}>(
   });
 }
 
+const appConfigMap = new Map<string, Promise<ParcelConfigObject>>();
+
 export function loadMicroApp<T extends object = {}>(
   app: LoadableApp<T>,
   configuration?: FrameworkConfiguration,
   lifeCycles?: FrameworkLifeCycles<T>,
 ): MicroApp {
-  const { props } = app;
-  return mountRootParcel(() => loadApp(app, configuration ?? frameworkConfiguration, lifeCycles), {
-    domElement: document.createElement('div'),
-    ...props,
-  });
+  const { props, name } = app;
+
+  const getContainerXpath = (container: string | HTMLElement): string | void => {
+    const containerElement = typeof container === 'string' ? document.querySelector(container) : container;
+    if (containerElement) {
+      return getXPathForElement(containerElement, document);
+    }
+
+    return undefined;
+  };
+
+  /**
+   * using name + container xpath as the micro app instance id,
+   * it means if you rendering a micro app to a dom which have been rendered before,
+   * the micro app would not load and evaluate its lifecycles again
+   */
+  const memorizedLoadingFn = async (): Promise<ParcelConfigObject> => {
+    const container = 'container' in app ? app.container : undefined;
+    if (container) {
+      const xpath = getContainerXpath(container);
+      if (xpath) {
+        const parcelConfig = appConfigMap.get(`${name}-${xpath}`);
+        if (parcelConfig) return parcelConfig;
+      }
+    }
+
+    const parcelConfig = loadApp(app, configuration ?? frameworkConfiguration, lifeCycles);
+
+    if (container) {
+      const xpath = getContainerXpath(container);
+      if (xpath)
+        appConfigMap.set(
+          `${name}-${xpath}`,
+          // empty bootstrap hook which should not run twice while it calling from cached micro app
+          parcelConfig.then(config => ({ ...config, bootstrap: () => Promise.resolve() })),
+        );
+    }
+
+    return parcelConfig;
+  };
+
+  return mountRootParcel(memorizedLoadingFn, { domElement: document.createElement('div'), ...props });
 }
 
 export function start(opts: FrameworkConfiguration = {}) {

src/utils.ts

@@ -126,3 +126,40 @@ export function isEnableScopedCSS(opt: FrameworkConfiguration) {
 
   return !!opt.sandbox.experimentalStyleIsolation;
 }
+
+/**
+ * copy from https://developer.mozilla.org/zh-CN/docs/Using_XPath
+ * @param el
+ * @param xml
+ */
+export function getXPathForElement(el: Node, xml: Document) {
+  let xpath = '';
+  let pos;
+  let tmpEle;
+  let element = el;
+
+  while (element !== xml.documentElement) {
+    pos = 0;
+    tmpEle = element;
+    while (tmpEle) {
+      if (tmpEle.nodeType === 1 && tmpEle.nodeName === element.nodeName) {
+        // If it is ELEMENT_NODE of the same name
+        pos += 1;
+      }
+      tmpEle = tmpEle.previousSibling;
+    }
+
+    xpath = `*[name()='${element.nodeName}' and namespace-uri()='${
+      element.namespaceURI === null ? '' : element.namespaceURI
+    }'][${pos}]/${xpath}`;
+
+    element = element.parentNode!;
+  }
+
+  xpath = `/*[name()='${xml.documentElement.nodeName}' and namespace-uri()='${
+    element.namespaceURI === null ? '' : element.namespaceURI
+  }']/${xpath}`;
+  xpath = xpath.replace(/\/$/, '');
+
+  return xpath;
+}