recalculate the insertion index after normalizing a node

[romainmenke]

see : #1778

Current context :

1. call insertAfter(exist, existingSibling)
2. set the value of exist to the index of the node in this.nodes
3. call this.normalize()
4. this.normalize() removes existingSibling from it's parent. (which is this)
5. exist is still the pre-calculated index
6. this.nodes has changed and the indices have changed because existingSibling was removed from it's parent
7. 🔥

  insertAfter(exist, add) {
    exist = this.index(exist)

    let nodes = this.normalize(add, this.proxyOf.nodes[exist]).reverse()
    for (let node of nodes) this.proxyOf.nodes.splice(exist + 1, 0, node)

    let index
    for (let id in this.indexes) {
      index = this.indexes[id]
      if (exist < index) {
        this.indexes[id] = index + nodes.length
      }
    }

    this.markDirty()

    return this
  }

normalize(nodes, sample) {
    // ...

    let processed = nodes.map(i => {
      /* c8 ignore next */
      if (!i[my]) Container.rebuild(i)
      i = i.proxyOf
      if (i.parent) i.parent.removeChild(i)
      if (i[isClean]) markDirtyUp(i)
      if (typeof i.raws.before === 'undefined') {
        if (sample && typeof sample.raws.before !== 'undefined') {
          i.raws.before = sample.raws.before.replace(/\S/g, '')
        }
      }
      i.parent = this.proxyOf
      return I
    })

    // ...
  }

---

Proposed fix

1. call insertAfter(exist, existingSibling)
2. set the value of existIndex to the index of the node in this.nodes
3. call this.normalize()
4. this.normalize() removes existingSibling from it's parent. (which is this)
5. set the value of existIndex to the index of the node in this.nodes (re-calculate)
6. continue

  insertAfter(exist, add) {
    let existIndex = this.index(exist)
    let nodes = this.normalize(add, this.proxyOf.nodes[existIndex]).reverse()
    existIndex = this.index(exist)
    for (let node of nodes) this.proxyOf.nodes.splice(existIndex + 1, 0, node)

    let index
    for (let id in this.indexes) {
      index = this.indexes[id]
      if (existIndex < index) {
        this.indexes[id] = index + nodes.length
      }
    }

    this.markDirty()

    return this
  }

[ai]

Released in 8.4.17.

[romainmenke]

@ai Thank you for reviewing and releasing this 🙇