Why assign `this` to `self` and run `self.method()`?

Question

I\'m reading the source from mongoose

Collection.prototype.onOpen = function () {
  var self = this;
  this.buffer = false;
  self.doQueue();
};

<

Answer 1

The only reason you would usually do that is if the call to doQueue() is inside a block that will change the value of this such as another function.

In this case however it doesn't serve any purpose and was probably a remnant of older code that was not changed back.