initial commit

packages/bridge/src/path/index.ts

@@ -0,0 +1,38 @@
+import { SyncDoc, Path } from '../model'
+import { NodeJSON } from 'slate'
+
+export const isTree = (node: NodeJSON): any => node.object !== 'text'
+
+export const getTarget = (doc: SyncDoc, path: Path) => {
+  const iterate = (current: any, idx: number) => {
+    if (!isTree(current) || !current.nodes) {
+      throw new TypeError(
+        `path ${path.toString()} does not match tree ${JSON.stringify(current)}`
+      )
+    }
+
+    return current.nodes[idx]
+  }
+
+  return path.reduce(iterate, doc.document)
+}
+
+export const getParentPath = (
+  path: Path,
+  level: number = 1
+): [number, Path] => {
+  if (level > path.size) {
+    throw new TypeError('requested ancestor is higher than root')
+  }
+
+  return [path.get(path.size - level), path.slice(0, path.size - level) as Path]
+}
+
+export const getParent = (
+  doc: SyncDoc,
+  path: Path,
+  level = 1
+): [NodeJSON, number] => {
+  const [idx, parentPath] = getParentPath(path, level)
+  return [getTarget(doc, parentPath), idx]
+}