Joins in Javascript

Question

I have 2 lists of objects:

people = 
[{id: 1, name: \"Tom\", carid: 1},
 {id: 2, name: \"Bob\", carid: 1},
 {id: 3, name: \"Sir Benjamin Rogan-Josh IV\", car         


        

Answer 1

Linq.js http://linqjs.codeplex.com/ will do joins along with many other things

Answer 2

This example uses Lodash to left join the first matched object. Not quite what the question asks, but I found a similar answer helpful.

var leftTable = [{
  leftId: 4,
  name: 'Will'
}, {
  leftId: 3,
  name: 'Michael'
}, {
  leftId: 8,
  name: 'Susan'
}, {
  leftId: 2,
  name: 'Bob'
}];

var rightTable = [{
  rightId: 1,
  color: 'Blue'
}, {
  rightId: 8,
  color: 'Red'
}, {
  rightId: 2,
  color: 'Orange'
}, {
  rightId: 7,
  color: 'Red'
}];

console.clear();

function leftJoinSingle(leftTable, rightTable, leftId, rightId) {
  var joinResults = [];

  _.forEach(leftTable, function(left) {
  	      var findBy = {};
      findBy[rightId] = left[leftId];

      var right = _.find(rightTable, findBy),
          result = _.merge(left, right);

      joinResults.push(result);
  })

  return joinResults;
}


var joinedArray = leftJoinSingle(leftTable, rightTable, 'leftId', 'rightId');
console.log(JSON.stringify(joinedArray, null, '\t'));

Results

[
	{
		"leftId": 4,
		"name": "Will"
	},
	{
		"leftId": 3,
		"name": "Michael"
	},
	{
		"leftId": 8,
		"name": "Susan",
		"rightId": 8,
		"color": "Red"
	},
	{
		"leftId": 2,
		"name": "Bob",
		"rightId": 2,
		"color": "Orange"
	}
]