typicaljoe/taffyjoin.html

## taffyjoin.html
<html>
<head>
<script src="https://github.com/typicaljoe/taffydb/raw/master/taffy.js"></script>
<script>

/*

Taffy innerJoin Extension (OCD edition)
=======================================

How to Use
**********

left_table.innerJoin( right_table, condition1 <,... conditionN> )

A condition can take one of 2 forms:

  1. An ARRAY with 2 or 3 values:
  A column name from the left table, an optional comparison string,
  and column name from the right table.  The condition passes if the test
  indicated is true.   If the condition string is omitted, '===' is assumed.
  EXAMPLES: [ 'last_used_time', '>=', 'current_use_time' ], [ 'user_id','id' ]

  2. A FUNCTION:
  The function receives a left table row and right table row during the
  cartesian join.  If the function returns true for the rows considered,
  the merged row is included in the result set.
  EXAMPLE: function (l,r){ return l.name === r.label; }

Conditions are considered in the order they are presented.  Therefore the best
performance is realized when the least expensive and highest prune-rate
conditions are placed first, since if they return false Taffy skips any
further condition tests.

Other notes
***********

This code passes jslint with the exception of 2 warnings about
the '==' and '!=' lines.  We can't do anything about that short of
deleting the lines.

Credits
*******

Heavily based upon the work of Ian Toltz.
Revisions to API by Michael Mikowski.
Code convention per standards in http://manning.com/mikowski

*/

/*jslint           browser : true,   continue : true,
 devel  : true,    indent : 2,       maxerr  : 50,
 newcap : true,  plusplus : true,    regexp  : true,
 sloppy : true,      vars : true,     white  : true
*/

/*global TAFFY */

(function () {
  var innerJoinFunction = (function () {
    var fnCompareList, fnCombineRow, fnMain;

    fnCompareList = function ( left_row, right_row, arg_list ) {
      var data_lt, data_rt, op_code, error;

      if ( arg_list.length === 2 ){
        data_lt = left_row[arg_list[0]];
        op_code = '===';
        data_rt = right_row[arg_list[1]];
      }
      else {
        data_lt = left_row[arg_list[0]];
        op_code = arg_list[1];
        data_rt = right_row[arg_list[2]];
      }

      switch ( op_code ){
        case '===' : return data_lt === data_rt;
        case '!==' : return data_lt !== data_rt;
        case '<'   : return data_lt <   data_rt;
        case '>'   : return data_lt >   data_rt;
        case '<='  : return data_lt <=  data_rt;
        case '>='  : return data_lt >=  data_rt;
        case '=='  : return data_lt ==  data_rt;
        case '!='  : return data_lt !=  data_rt;
        default :
          throw String(op_code) + ' is not supported';
      }
    };

    fnCombineRow = function ( left_row, right_row ) {
      var out_map = {}, i, prefix;

      for ( i in left_row ){
        if ( left_row.hasOwnProperty(i)){
          out_map[i] = left_row[i];
         }
      }
      for (i in right_row) {
        if ( right_row.hasOwnProperty(i) && i !== '___id' && i !== '___s' ) {
          prefix = !TAFFY.isUndefined(out_map[i]) ? 'right_' : '';
          out_map[prefix + String(i) ] = right_row[i];
        }
      }
      return out_map;
    };

    fnMain = function ( table ) {
      var
        right_table, i,
        arg_list    = arguments,
        arg_length  = arg_list.length,
        result_list = []
        ;

      if ( typeof table.filter !== 'function' ) {
        if ( table.TAFFY) { right_table = table(); }
        else {
          throw 'TAFFY DB or result not supplied';
        }
      }
      else { right_table = table; }

      this.context({
        results: this.getDBI().query( this.context() )
      });

      TAFFY.each(this.context().results, function ( left_row ){
        right_table.each( function ( right_row ) {
          var arg_data, is_ok = true;
          CONDITION:
          for (i = 1; i < arg_length; i++ ) {
            arg_data = arg_list[i];
            if (typeof arg_data === 'function'){
              is_ok = arg_data( left_row, right_row );
            }
            else if ( typeof arg_data === 'object' && arg_data.length ){
              is_ok = fnCompareList( left_row, right_row, arg_data );
            }
            else {
              is_ok = false;
            }

            if ( ! is_ok ) { break CONDITION; } // short circuit
          }

          if ( is_ok ){
            result_list.push( fnCombineRow(left_row, right_row ) );
          }
        });
      });
      return TAFFY(result_list)();
    };

    return fnMain;
  }());

  TAFFY.extend('join', innerJoinFunction);
}());

var city_db, state_db;

city_db = TAFFY([
  {name:'New York',state:'NY'},
  {name:'Las Vegas',state:'NV'},
  {name:'Boston',state:'MA'}
]);

state_db = TAFFY([
  {name: 'New York', abbreviation: 'NY'},
  {name: 'Nevada', abbreviation: 'NV'},
  {name: 'Massachusetts', abbreviation: 'MA'}
]);

console.log('simple join:');
city_db()
  .join( state_db, [ 'state', 'abbreviation' ])
  .each( function (r) { console.log(r); } )
  ;

console.log('join with pre-filtered DB:');
city_db()
  .join( state_db({abbreviation: 'NV'}), ['state', 'abbreviation'] )
  .each(function (r) { console.log(r); })
  ;

console.log('Array Join, Not Equal:');
city_db()
  .join(state_db, ['state', '!==', 'abbreviation'])
  .each( function (r) { console.log(r);} )
  ;

console.log('Function join, state name contains abbreviation:');
city_db()
  .join(
    state_db,
    function (l, r) {
      return (r.name.toLowerCase().indexOf(l.state.toLowerCase()) >= 0);
    }
  ).each(function (r) { console.log(r);})
  ;

</script>
</head>
<body>
</body>
</html>
	<html>
	<head>
	<script src="https://github.com/typicaljoe/taffydb/raw/master/taffy.js"></script>
	<script>

	/*

	Taffy innerJoin Extension (OCD edition)
	=======================================

	How to Use
	**********

	left_table.innerJoin( right_table, condition1 <,... conditionN> )

	A condition can take one of 2 forms:

	1. An ARRAY with 2 or 3 values:
	A column name from the left table, an optional comparison string,
	and column name from the right table. The condition passes if the test
	indicated is true. If the condition string is omitted, '===' is assumed.
	EXAMPLES: [ 'last_used_time', '>=', 'current_use_time' ], [ 'user_id','id' ]

	2. A FUNCTION:
	The function receives a left table row and right table row during the
	cartesian join. If the function returns true for the rows considered,
	the merged row is included in the result set.
	EXAMPLE: function (l,r){ return l.name === r.label; }

	Conditions are considered in the order they are presented. Therefore the best
	performance is realized when the least expensive and highest prune-rate
	conditions are placed first, since if they return false Taffy skips any
	further condition tests.

	Other notes
	***********

	This code passes jslint with the exception of 2 warnings about
	the '==' and '!=' lines. We can't do anything about that short of
	deleting the lines.

	Credits
	*******

	Heavily based upon the work of Ian Toltz.
	Revisions to API by Michael Mikowski.
	Code convention per standards in http://manning.com/mikowski

	*/

	/*jslint browser : true, continue : true,
	devel : true, indent : 2, maxerr : 50,
	newcap : true, plusplus : true, regexp : true,
	sloppy : true, vars : true, white : true
	*/

	/global TAFFY /

	(function () {
	var innerJoinFunction = (function () {
	var fnCompareList, fnCombineRow, fnMain;

	fnCompareList = function ( left_row, right_row, arg_list ) {
	var data_lt, data_rt, op_code, error;

	if ( arg_list.length === 2 ){
	data_lt = left_row[arg_list[0]];
	op_code = '===';
	data_rt = right_row[arg_list[1]];
	}
	else {
	data_lt = left_row[arg_list[0]];
	op_code = arg_list[1];
	data_rt = right_row[arg_list[2]];
	}

	switch ( op_code ){
	case '===' : return data_lt === data_rt;
	case '!==' : return data_lt !== data_rt;
	case '<' : return data_lt < data_rt;
	case '>' : return data_lt > data_rt;
	case '<=' : return data_lt <= data_rt;
	case '>=' : return data_lt >= data_rt;
	case '==' : return data_lt == data_rt;
	case '!=' : return data_lt != data_rt;
	default :
	throw String(op_code) + ' is not supported';
	}
	};

	fnCombineRow = function ( left_row, right_row ) {
	var out_map = {}, i, prefix;

	for ( i in left_row ){
	if ( left_row.hasOwnProperty(i)){
	out_map[i] = left_row[i];
	}
	}
	for (i in right_row) {
	if ( right_row.hasOwnProperty(i) && i !== '___id' && i !== '___s' ) {
	prefix = !TAFFY.isUndefined(out_map[i]) ? 'right_' : '';
	out_map[prefix + String(i) ] = right_row[i];
	}
	}
	return out_map;
	};

	fnMain = function ( table ) {
	var
	right_table, i,
	arg_list = arguments,
	arg_length = arg_list.length,
	result_list = []
	;

	if ( typeof table.filter !== 'function' ) {
	if ( table.TAFFY) { right_table = table(); }
	else {
	throw 'TAFFY DB or result not supplied';
	}
	}
	else { right_table = table; }

	this.context({
	results: this.getDBI().query( this.context() )
	});

	TAFFY.each(this.context().results, function ( left_row ){
	right_table.each( function ( right_row ) {
	var arg_data, is_ok = true;
	CONDITION:
	for (i = 1; i < arg_length; i++ ) {
	arg_data = arg_list[i];
	if (typeof arg_data === 'function'){
	is_ok = arg_data( left_row, right_row );
	}
	else if ( typeof arg_data === 'object' && arg_data.length ){
	is_ok = fnCompareList( left_row, right_row, arg_data );
	}
	else {
	is_ok = false;
	}

	if ( ! is_ok ) { break CONDITION; } // short circuit
	}

	if ( is_ok ){
	result_list.push( fnCombineRow(left_row, right_row ) );
	}
	});
	});
	return TAFFY(result_list)();
	};

	return fnMain;
	}());

	TAFFY.extend('join', innerJoinFunction);
	}());

	var city_db, state_db;

	city_db = TAFFY([
	{name:'New York',state:'NY'},
	{name:'Las Vegas',state:'NV'},
	{name:'Boston',state:'MA'}
	]);

	state_db = TAFFY([
	{name: 'New York', abbreviation: 'NY'},
	{name: 'Nevada', abbreviation: 'NV'},
	{name: 'Massachusetts', abbreviation: 'MA'}
	]);

	console.log('simple join:');
	city_db()
	.join( state_db, [ 'state', 'abbreviation' ])
	.each( function (r) { console.log(r); } )
	;

	console.log('join with pre-filtered DB:');
	city_db()
	.join( state_db({abbreviation: 'NV'}), ['state', 'abbreviation'] )
	.each(function (r) { console.log(r); })
	;

	console.log('Array Join, Not Equal:');
	city_db()
	.join(state_db, ['state', '!==', 'abbreviation'])
	.each( function (r) { console.log(r);} )
	;

	console.log('Function join, state name contains abbreviation:');
	city_db()
	.join(
	state_db,
	function (l, r) {
	return (r.name.toLowerCase().indexOf(l.state.toLowerCase()) >= 0);
	}
	).each(function (r) { console.log(r);})
	;

	</script>
	</head>
	<body>
	</body>
	</html>