Tree Climber

Performs a traversal of a tree. Calls a visitor function on each node.

Install

npm install tree-climber --save

Usage

  var tree = require('tree-climber');
  var Promise = require('promise');

  tree.climb({
    path1: {
      node1: 'value1',
      path2: {
        node2: 'value2',
        path3: {
          node3: 'value3'
        }
      }
    }
  }, visitor);

  function visitor (key, value, path) {};
  // Calls to visitor will be:
  // 'node1', 'value1', 'path1.node1'
  // 'node2', 'value2', 'path1.path2.node2'
  // 'node3', 'value3', 'path1.path2.path3.node3'

  tree.climbAsync({
    path1: {
      node1: 'value1',
      path2: {
        node2: 'value2',
        path3: {
          node3: 'value3'
        }
      }
    }
  }, visitorAsync)
  .then(console.log);
  // ['foo', 'foo', 'foo']

  function visitorAsync (key, value, path) {
    console.log(arguments);
    return Promise.resolve('foo');
  }

  // Calls to visitor will be:
  // 'node1', 'value1', 'path1.node1'
  // 'node2', 'value2', 'path1.path2.node2'
  // 'node3', 'value3', 'path1.path2.path3.node3'

tree.climb(obj, visitor, sep)

• obj {Array|Object} The "tree" to visit each node on.
• visitor {Function} Called when visiting a node.
  • key {String} The key of this node.
  • value {Mixed} The value of this node.
  • path {String} The full path of the tree to this node.
• sep {String} An optional override for the path separator. Defaults to ..

tree.climbAsync(obj, visitor, sep)

• obj {Array|Object} The "tree" to visit each node on.
• visitor {Function} Called when visiting a node.
  • key {String} The key of this node.
  • value {Mixed} The value of this node.
  • path {String} The full path of the tree to this node.
  • return: {Promise} A promise to pend resolving other nodes in the tree on.
• sep {String} An optional override for the path separator. Defaults to ..

Allows the user to perform asynchronous work on each node of the tree. Chains promises in such a way that race conditions are avoided. As an example if there was a path a->b->c and a->b->d, tree.climbAsync would wait for one of those paths to resolve before processing the other one since they share a common ancestor.