feat(ssr): compiler-ssr support for Suspense

packages/compiler-ssr/src/transforms/ssrTransformSuspense.ts

@@ -0,0 +1,78 @@
+import {
+  ComponentNode,
+  TransformContext,
+  buildSlots,
+  createFunctionExpression,
+  FunctionExpression,
+  TemplateChildNode,
+  createCallExpression,
+  SlotsExpression
+} from '@vue/compiler-dom'
+import {
+  SSRTransformContext,
+  processChildrenAsStatement
+} from '../ssrCodegenTransform'
+import { SSR_RENDER_SUSPENSE } from '../runtimeHelpers'
+
+const wipMap = new WeakMap<ComponentNode, WIPEntry>()
+
+interface WIPEntry {
+  slotsExp: SlotsExpression
+  wipSlots: Array<{
+    fn: FunctionExpression
+    children: TemplateChildNode[]
+  }>
+}
+
+// phase 1
+export function ssrTransformSuspense(
+  node: ComponentNode,
+  context: TransformContext
+) {
+  return () => {
+    if (node.children.length) {
+      const wipEntry: WIPEntry = {
+        slotsExp: null as any,
+        wipSlots: []
+      }
+      wipMap.set(node, wipEntry)
+      wipEntry.slotsExp = buildSlots(node, context, (_props, children, loc) => {
+        const fn = createFunctionExpression(
+          [`_push`],
+          undefined, // no return, assign body later
+          true, // newline
+          false, // suspense slots are not treated as normal slots
+          loc
+        )
+        wipEntry.wipSlots.push({
+          fn,
+          children
+        })
+        return fn
+      }).slots
+    }
+  }
+}
+
+// phase 2
+export function ssrProcessSuspense(
+  node: ComponentNode,
+  context: SSRTransformContext
+) {
+  // complete wip slots with ssr code
+  const wipEntry = wipMap.get(node)
+  if (!wipEntry) {
+    return
+  }
+  const { slotsExp, wipSlots } = wipEntry
+  for (let i = 0; i < wipSlots.length; i++) {
+    const { fn, children } = wipSlots[i]
+    fn.body = processChildrenAsStatement(children, context)
+  }
+  // _push(ssrRenderSuspense(slots))
+  context.pushStatement(
+    createCallExpression(`_push`, [
+      createCallExpression(context.helper(SSR_RENDER_SUSPENSE), [slotsExp])
+    ])
+  )
+}