Function combineFragments

packages/core/src/language/fragment_adapter.ts:137–165

(fragment1: SplootFragment, fragment2: SplootFragment)

// Note: fragment1 will always be added to fragment2, not the other way around.
export function combineFragments(fragment1: SplootFragment, fragment2: SplootFragment): SplootFragment {
  if (fragment1 === null) {
    return fragment2
  }
  if (fragment1.nodeCategory === fragment2.nodeCategory) {
    return new SplootFragment(fragment1.nodes.concat(fragment2.nodes), fragment2.nodeCategory)
  }

  const destCategory = fragment2.nodeCategory

  const adapters = fragmentAdapterMapping.get(fragment1.nodeCategory)
  if (adapters && adapters.has(destCategory)) {
    const node = adapters.get(destCategory)(fragment1)
    return new SplootFragment([node, ...fragment2.nodes], fragment2.nodeCategory)
  }

  const valid = fragment1.nodes.filter((node) => isAdaptableToPasteDesintation(node, destCategory))
  if (fragment1.nodes.length == valid.length) {
    const adaptedNodes = fragment1.nodes.map((node) => {
      const adaptedNode = adaptNodeToPasteDestination(node, destCategory)
      // Need to clean here so that empty expressions get removed from statement nodes.
      adaptedNode.clean()
      return adaptedNode
    })
    return new SplootFragment(adaptedNodes.concat(fragment2.nodes), fragment2.nodeCategory)
  }

  return fragment2
}