src/fauxton/app/addons/pouchdb/pouch.collate.js

/*
 * NOTE:
 * This temporarily uses the PouchDB map reduce implementation
 * These files are modified locally until we make a more general version and
 * push it back upstream.
 * Original file:
 * https://github.com/daleharvey/pouchdb/blob/master/src/pouch.collate.js
 */

/*
(function() {
  // a few hacks to get things in the right place for node.js
  if (typeof module !== 'undefined' && module.exports) {
    module.exports = Pouch;
  }
*/

define([
  "app",

  "api",

  // Modules
  "addons/pouchdb/pouch.collate.js"
],

function(app, FauxtonAPI, Collate) {
  var Pouch = {};

  Pouch.collate = function(a, b) {
    var ai = collationIndex(a);
    var bi = collationIndex(b);
    if ((ai - bi) !== 0) {
      return ai - bi;
    }
    if (a === null) {
      return 0;
    }
    if (typeof a === 'number') {
      return a - b;
    }
    if (typeof a === 'boolean') {
      return a < b ? -1 : 1;
    }
    if (typeof a === 'string') {
      return stringCollate(a, b);
    }
    if (Array.isArray(a)) {
      return arrayCollate(a, b);
    }
    if (typeof a === 'object') {
      return objectCollate(a, b);
    }
  };

  var stringCollate = function(a, b) {
    // See: https://github.com/daleharvey/pouchdb/issues/40
    // This is incompatible with the CouchDB implementation, but its the
    // best we can do for now
    return (a === b) ? 0 : ((a > b) ? 1 : -1);
  };

  var objectCollate = function(a, b) {
    var ak = Object.keys(a), bk = Object.keys(b);
    var len = Math.min(ak.length, bk.length);
    for (var i = 0; i < len; i++) {
      // First sort the keys
      var sort = Pouch.collate(ak[i], bk[i]);
      if (sort !== 0) {
        return sort;
      }
      // if the keys are equal sort the values
      sort = Pouch.collate(a[ak[i]], b[bk[i]]);
      if (sort !== 0) {
        return sort;
      }

    }
    return (ak.length === bk.length) ? 0 :
      (ak.length > bk.length) ? 1 : -1;
  };

  var arrayCollate = function(a, b) {
    var len = Math.min(a.length, b.length);
    for (var i = 0; i < len; i++) {
      var sort = Pouch.collate(a[i], b[i]);
      if (sort !== 0) {
        return sort;
      }
    }
    return (a.length === b.length) ? 0 :
      (a.length > b.length) ? 1 : -1;
  };

  // The collation is defined by erlangs ordered terms
  // the atoms null, true, false come first, then numbers, strings,
  // arrays, then objects
  var collationIndex = function(x) {
    var id = ['boolean', 'number', 'string', 'object'];
    if (id.indexOf(typeof x) !== -1) {
      if (x === null) {
        return 1;
      }
      return id.indexOf(typeof x) + 2;
    }
    if (Array.isArray(x)) {
      return 4.5;
    }
  };

  return Pouch;

});