fix: v-for update on move (#79)

src/directives/for.ts

@@ -124,38 +124,43 @@ export const _for = (el: Element, exp: string, ctx: Context) => {
  blocks = childCtxs.map((s) => mountBlock(s, anchor))
  mounted = true
  } else {
- const nextBlocks: Block[] = []
  for (let i = 0; i < blocks.length; i++) {
  if (!keyToIndexMap.has(blocks[i].key)) {
  blocks[i].remove()
  }
  }
-
+
+ const nextBlocks: Block[] = []
  let i = childCtxs.length
+ let nextBlock: Block | undefined
+ let prevMovedBlock: Block | undefined
  while (i--) {
  const childCtx = childCtxs[i]
  const oldIndex = prevKeyToIndexMap.get(childCtx.key)
- const next = childCtxs[i + 1]
- const nextBlockOldIndex = next && prevKeyToIndexMap.get(next.key)
- const nextBlock =
- nextBlockOldIndex == null ? undefined : blocks[nextBlockOldIndex]
+ let block
  if (oldIndex == null) {
  // new
- nextBlocks[i] = mountBlock(
+ block = mountBlock(
  childCtx,
  nextBlock ? nextBlock.el : anchor
  )
  } else {
  // update
- const block = (nextBlocks[i] = blocks[oldIndex])
+ block = blocks[oldIndex]
  Object.assign(block.ctx.scope, childCtx.scope)
  if (oldIndex !== i) {
  // moved
- if (blocks[oldIndex + 1] !== nextBlock) {
+ if (
+ blocks[oldIndex + 1] !== nextBlock || 
+ // If the next has moved, it must move too
+ prevMovedBlock === nextBlock
+ ) {
+ prevMovedBlock = block
  block.insert(parent, nextBlock ? nextBlock.el : anchor)
  }
  }
  }
+ nextBlocks.unshift(nextBlock = block)
  }
  blocks = nextBlocks
  }