Class Tree

src/lib/parser/tree.ts:55–364

const treeProperties = Object.keys(emptyTree) as (keyof TreeObject)[];

export class Tree implements TreeObject {
  nodeMap: Record<string, Node>; // A map from node ID to the Node object for quick lookup.
  text: string; // The raw text content of the JSON string.
  nestNodeMap?: Record<string, Node>; // A map from node ID to the root Node of a nested JSON string that has been parsed into its own tree.
  errors?: ContextError[]; // An array of parsing errors.
  version?: number; // A version number for the tree, can be used to track changes.
  needReset?: boolean; // If true, reset the editor's cursor to the beginning and the graph's viewport.

  constructor(text: string = "") {
    this.nodeMap = {};
    this.text = text;
  }

  static assign<A extends Tree | TreeObject, B extends Tree | TreeObject>(a: A, b: B) {
    for (const key of treeProperties) {
      if (b[key] !== undefined) {
        (a as any)[key] = b[key];
      }
    }
    return a;
  }

  static fromObject(treeObject: TreeObject, nestNodeMap?: Record<string, Node>) {
    const tree = Tree.assign(new Tree(), treeObject);
    tree.nestNodeMap = nestNodeMap;
    return tree;
  }

  toObject(): TreeObject {
    return Tree.assign({} as TreeObject, this);
  }

  valid() {
    return this.root() && !this.hasError();
  }

  root() {
    return this.node(rootMarker);
  }

  isRoot(node: Node) {
    return node.id === rootMarker;
  }

  node(id: string) {
    return this.nodeMap[id];
  }

  getNodeToken(node: Node) {
    return this.text.slice(node.offset, node.offset + node.length);
  }

  getParent(id: string) {
    const parentId = getParentId(id);
    return parentId !== undefined ? this.nodeMap[parentId] : undefined;
  }

  getChild(node: Node, key: string): Node | undefined {