Method getOrCreate

lib/mapping/tree.js:58–118

* Gets the existing item in the tree or creates a new one with the value provided by valueHandler * @param {Iterator} keyIterator * @param {Function} valueHandler * @return {Object}

(keyIterator, valueHandler)

   * @return {Object}
   */
  getOrCreate(keyIterator, valueHandler) {
    if (typeof keyIterator.next !== 'function') {
      keyIterator = keyIterator[Symbol.iterator]();
    }
    let node = this;
    let isMatch = false;
    let item = keyIterator.next();
    while (true) {
      let newBranch;
      // Check node keys at position 1 and above
      for (let i = 1; i < node.key.length; i++) {
        if (item.done || node.key[i] !== item.value) {
          // We should branch out
          newBranch = this._createBranch(node, i, item.done, valueHandler);
          break;
        }
        item = keyIterator.next();
      }

      if (item.done) {
        isMatch = true;
        break;
      }

      if (newBranch !== undefined) {
        break;
      }

      const edges = node.edges;
      let nextNode;
      for (let i = 0; i < edges.length; i++) {
        const e = edges[i];
        if (e.key[0] === item.value) {
          // its a match
          nextNode = e;
          item = keyIterator.next();
          break;
        }
      }

      if (nextNode === undefined) {
        // Current node is the root for a new leaf
        break;
      }
      else {
        node = nextNode;
      }
    }

    if (!isMatch) {
      // Create using "node" as the root
      const value = valueHandler();
      node.edges.push(new Node(iteratorToArray(item.value, keyIterator), value));
      this._onItemAdded();
      return value;
    }
    if (node.value === null && node.edges.length > 0) {
      node.value = valueHandler();