gistfile1.js

function A() {
  function privateA() {}
  function privateB() {}
  
  function publicA() {
    // now this.publicB() here, just publicB() - safes typing and even if someone overrides publicB we still use the implementation from here
    // of course that latter might not be desired, in which case you'd write this.publicB() here
    return publicB() ? privateA() : privateB();
  }
  this.publicA = publicA;
  
  function publicB() {}
  this.publicB = publicB;
}