src/basis/data/dataset/Merge.js
function(rule){
    rule = basis.getter(rule || UNION);

    if (this.rule !== rule)
    {
      var oldRule = this.rule;

      this.rule = rule;
      this.emit_ruleChanged(oldRule);

      return this.applyRule();
    }
  }
function(rule){
    rule = basis.getter(rule || UNION);

    if (this.rule !== rule)
    {
      var oldRule = this.rule;

      this.rule = rule;
      this.emit_ruleChanged(oldRule);

      return this.applyRule();
    }
  }
function ( rule ) { rule = basis . getter ( rule || UNION ) ; if ( this . rule !== rule ) { var oldRule = this . rule ; this . rule = rule ; this . emit_ruleChanged ( oldRule ) ; return this . applyRule ( ) ; } }
Set new merge rule for dataset. Some types are available in basis.data.Dataset.Merge
@param {function(count:number, sourceCount:number):boolean|string} rule New rule.
@return {Object} Delta of member changes.
Set new merge rule for dataset . Some types are available in basis . data . Dataset . Merge