example of iterator for the `where` clause from the `criteria` query key of a stage 2 query in waterline 0.13 / sails v1 (also works for stage 3 queries)

example-of-iterator-for-where-clause-of-stage-2-query-in-waterline-0.13-and-sails-v1.js

// ====================================================================================
// Example of iterating over the `where` clause from a stage 2 query from Waterline.
// (the example below attempts to demonstrate a few of the most useful guarantees)
// 
// > Mostly pay attention to the structure.  Other than that, you can safely assume
// > that, in short, everything is valid (+in a schema-aware way), guaranteed.
// ====================================================================================

/*  ~%° before iterating  */

(function _iterateRecursive(branch) {
  
  //  ╔═╗╦═╗╔═╗╔╦╗╦╔═╗╔═╗╔╦╗╔═╗
  //  ╠═╝╠╦╝║╣  ║║║║  ╠═╣ ║ ║╣ 
  //  ╩  ╩╚═╚═╝═╩╝╩╚═╝╩ ╩ ╩ ╚═╝
  // If this branch contains a predicate...
  if (branch.and || branch.or) {

    /*  ~%° before AND/OR  */

    _.each(whereClause.and || whereClause.or, function (conjunctOrDisjunct){

      /*  ~%° before conjunct/disjunct  */
      
      // Take the recursive step.
      _iterateRecursive(conjunctOrDisjunct);

      /*  ~%° after conjunct/disjunct  */

    });

    /*  ~%° after AND/OR  */

    return;
  }//-•


  //  ╔═╗╔═╗╔╗╔╔═╗╔╦╗╦═╗╔═╗╦╔╗╔╔╦╗
  //  ║  ║ ║║║║╚═╗ ║ ╠╦╝╠═╣║║║║ ║ 
  //  ╚═╝╚═╝╝╚╝╚═╝ ╩ ╩╚═╩ ╩╩╝╚╝ ╩ 
  // Otherwise IWMIH, this branch contains a constraint.
  
  // Figure out what we're filtering by.
  // (e.g. "emailAddress")
  var filterBy = _.keys(branch)[0];
  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
  // ^^ note how we can trust that there's exactly one key
  // (that's b/c any extra modifiers have been expanded into
  // an `and` predicate via the "fracturing" process in Waterline
  // core)
  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
  
  // Now examine the constraint itself.
  // `constraint` is either:
  //  • a dictionary (a "complex constraint")
  //  • or a primitive (an "eq constraint").
  var constraint = branch[filterBy];


  /*  ~%° before constraint  */
  
  // If it is a complex constraint...
  if (_.isObject(constraint)) {

    /*  ~%° on complex constraint (will always have exactly ONE key) */

  }
  // Otherwise it is an eq constraint.
  else {

    /*  ~%° on eq constraint  */
    
  }

  /*  ~%° after constraint  */

})(someCriteria.where);

/*  ~%° after iterating  */

Note that this example is also equally valid for iterating over the where clause of the criteria QK of a stage 3 query (i.e. in an adapter)