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node_modules/@riotjs/lazy/index.next.js

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+import { component, pure } from 'riot'
+import { cleanNode } from '@riotjs/util/dom'
+
+// this object will contain all the components implementations lazy loaded
+const cache = new WeakMap()
+
+// expose the cache as static property
+lazy.cache = cache
+
+// static attribute in case we want to just export a lazy riot component
+lazy.export = function lazyExport(Loader, Component) {
+  // it could be that the user don't want to use a loader for whatever reason
+  const hasLoader = Loader && Component
+  const LazyComponent = hasLoader ? Component : Loader
+  const load = () => typeof LazyComponent === 'function' ? LazyComponent() : Promise.resolve(LazyComponent)
+  const cachedComponent = cache.get(LazyComponent)
+
+  return pure(({ slots, attributes, props }) => ({
+    mount(el, parentScope) {
+      this.el = el
+      this.isMounted = true
+      const mount = () => {
+        this.mountLazyComponent(parentScope)
+        this.el.dispatchEvent(new Event('load'))
+      }
+
+      if (cachedComponent) {
+        mount()
+      } else {
+        if (hasLoader) this.createManagedComponent(Loader, parentScope)
+
+        load().then(data => {
+          cache.set(LazyComponent, data.default || data)
+          mount()
+        })
+      }
+    },
+    createManagedComponent(Child, parentScope) {
+      this.component = component(Child)(this.el, props, {
+        attributes, slots, parentScope
+      })
+    },
+    mountLazyComponent(parentScope) {
+      // if this component was unmounted just return here
+      if (!this.isMounted) return
+
+      // unmount the loader if it was previously created
+      if (this.component) {
+        // unmount the bindings (keeping the root node)
+        this.component.unmount(true)
+        // clean the DOM
+        if (this.el.children.length) cleanNode(this.el)
+      }
+
+      // replace the old component instance with the new lazy loaded component
+      this.createManagedComponent(cache.get(LazyComponent), parentScope)
+    },
+    update(parentScope) {
+      if (this.isMounted && this.component) this.component.update({}, parentScope)
+    },
+    unmount(...args) {
+      this.isMounted = false
+
+      if (this.component) this.component.unmount(...args)
+    }
+  }))
+}
+
+export default function lazy(Loader, Component) {
+  return {
+    name: 'lazy',
+    exports: lazy.export(Loader, Component)
+  }
+}