Nodejs从对象的函数内部调用对象的函数

Question

In the code below I am trying to call the function getCollection of the object DbModels from within a call to the getCollection function:

DbModels.prototype.addUser = function(Users, callback) { 
this.getCollection("seq", function(error, seq_collection) {
  if( error ) callback(error)
      else {
  var ID = seq_collection.find({_id: 'Users'}, {'seq': 1});
  console.log("ID is: "+ID);
  console.log(this.parent);
      this.getCollection("Users", function(error, sel_collection) {....

However, this is not working, because this is referring to the first getCollection. How can I call the getCollection function from within the call to the get Collection?

I already tries this.parent, but that doesn't do the trick.

Thanks!

Answer 1

store this to a variable beforehand:

DbModels.prototype.addUser = function(Users, callback) { 

var self = this;

this.getCollection("seq", function(error, seq_collection) {
  if( error ) callback(error)
      else {
  var ID = seq_collection.find({_id: 'Users'}, {'seq': 1});
  console.log("ID is: "+ID);
  console.log(this.parent);

      self.getCollection("Users", function(error, sel_collection) {....