Merge cwllections

collection-merge.js

var ar = [{date:'2015-01-01', data:15}, {date:'2015-02-01', data:18}, {date:'2015-02-05', data:10}, {date:'2015-02-06', data:25}];
var br = [{date:'2015-01-01', v:3}, {date:'2015-02-01', v:1}, {date:'2015-02-09', v:20}];
var merged = [];
for(var i=0;i<ar.length;i++){
  var check = 0;
  for(var j=0;j<br.length;j++){
    if(ar[i].date === br[j].date) {
      check = 1;
      merged.push({date: ar[i].date, data: ar[i].data, v: br[j].v});
      continue;
    }
  }
  if (check !== 1) {
    merged.push({date: ar[i].date, data: ar[i].data, v: 0});
  }
}