node package manager


Visit nodes in the tree asynchronously and sequentially. Supports promises.

Tree Visitor Async

Visit nodes in the tree asynchronously and sequentially. Support promises.

Asynchronous version of Tree Visitor. Actions can return a promise and .visit() returns a promise.

var fs = require('fs');
var Q = require('q');
var VisitorAsync = require('tree-visitor-async');
var nodes = [
{ type: 'import', value: 'path/to/file1' },
{ type: 'import', value: 'path/to/file2' },
function MyVisitorAsync() {}
MyVisitorAsync.prototype = new VisitorAsync();
MyVisitorAsync.prototype.visit_import = function (importNode) {
var deferred = Q.defer();
fs.readFile(importNode.value, 'utf8', deferred.makeNodeResolver());
return deferred.promise.then(function (content) {
new MyVisitorAsync().visit(nodes).then(function () {

Methods are passed to the returned promise as fulfill callbacks. So, for example, if a method throws an error or returns a rejected promise, subsequent nodes won't be visited.

this keyword in the fulfill & reject callbacks refers the created visitor object (e.g., new MyVisitorAsync() in the previous example).