wip: element transforms

packages/compiler-core/src/transforms/vIf.ts

@@ -0,0 +1,63 @@
+import { createDirectiveTransform } from '../transform'
+import {
+  NodeTypes,
+  ElementTypes,
+  ElementNode,
+  DirectiveNode,
+  IfBranchNode
+} from '../ast'
+import { createCompilerError, ErrorCodes } from '../errors'
+
+export const transformIf = createDirectiveTransform(
+  /^(if|else|else-if)$/,
+  (node, dir, context) => {
+    if (dir.name === 'if') {
+      context.replaceNode({
+        type: NodeTypes.IF,
+        loc: node.loc,
+        branches: [createIfBranch(node, dir)]
+      })
+    } else {
+      // locate the adjacent v-if
+      const siblings = context.parent.children
+      const comments = []
+      let i = siblings.indexOf(node)
+      while (i-- >= -1) {
+        const sibling = siblings[i]
+        if (__DEV__ && sibling && sibling.type === NodeTypes.COMMENT) {
+          context.removeNode(sibling)
+          comments.unshift(sibling)
+          continue
+        }
+        if (sibling && sibling.type === NodeTypes.IF) {
+          // move the node to the if node's branches
+          context.removeNode()
+          const branch = createIfBranch(node, dir)
+          if (__DEV__ && comments.length) {
+            branch.children = [...comments, ...branch.children]
+          }
+          sibling.branches.push(branch)
+        } else {
+          context.emitError(
+            createCompilerError(
+              dir.name === 'else'
+                ? ErrorCodes.X_ELSE_NO_ADJACENT_IF
+                : ErrorCodes.X_ELSE_IF_NO_ADJACENT_IF,
+              node.loc.start
+            )
+          )
+        }
+        break
+      }
+    }
+  }
+)
+
+function createIfBranch(node: ElementNode, dir: DirectiveNode): IfBranchNode {
+  return {
+    type: NodeTypes.IF_BRANCH,
+    loc: node.loc,
+    condition: dir.name === 'else' ? undefined : dir.exp,
+    children: node.tagType === ElementTypes.TEMPLATE ? node.children : [node]
+  }
+}