Query through Json object

Question

This is my JSON:

[{"Id":1,"Order":1,"IsDone":true,"Text":"abc","Date":"6/14/2014"},
 {"Id":2,"Order":2,"IsDone":false,"Text":"cde","Date":"6/15/2014"},
 {"Id":3,"Order":3,"IsDone":false,"Text":"fgh","Date":"6/16/2014"}]

What would be the most efficient way to get the count of IsDone == true?

Answer 1

You can use plain javascript iteration:

var a=[{"Id":1,"Order":1,"IsDone":true,"Text":"abc","Date":"6/14/2014"},{"Id":2,"Order":2,"IsDone":false,"Text":"cde","Date":"6/15/2014"},{"Id":3,"Order":3,"IsDone":false,"Text":"fgh","Date":"6/16/2014"}]

var ct=0;
a.forEach(function(entry) {
    if(entry.IsDone)ct++;
});
alert(ct);

Answer 2

Use grep fron jquery

var selectedArray = [{"Id":1,"Order":1,"IsDone":true,"Text":"abc","Date":"6/14/2014"},
{"Id":2,"Order":2,"IsDone":false,"Text":"cde","Date":"6/15/2014"},
{"Id":3,"Order":3,"IsDone":false,"Text":"fgh","Date":"6/16/2014"}]



selectedArray = jQuery.grep(selectedArray, function (el) { return el.IsDone == true;   });

 alert(selectedArray.length);

where seletedArray is your actual array

http://jsfiddle.net/QxV6K/

Answer 3

var data = [{"Id":1,"Order":1,"IsDone":true,"Text":"abc","Date":"6/14/2014"},{"Id":2,"Order":2,"IsDone":false,"Text":"cde","Date":"6/15/2014"},{"Id":3,"Order":3,"IsDone":false,"Text":"fgh","Date":"6/16/2014"}];

var count = data.filter(function (el) {
  return (el.IsDone === true);
});

alert(count.length);

DEMO

Answer 4

try this one

 var obj = [{"Id":1,"Order":1,"IsDone":true,"Text":"abc","Date":"6/14/2014"},
    {"Id":2,"Order":2,"IsDone":false,"Text":"cde","Date":"6/15/2014"},
    {"Id":3,"Order":3,"IsDone":false,"Text":"fgh","Date":"6/16/2014"}]

    var count = 0;
    for(i=0;i<obj.length;i--){
      count += (obj[i].IsDone) ? 1 : 0;
    }

Answer 5

In case you're trying to access an item from the example structure by id or name, without knowing it's position in the array, the easiest way to do it would be to use underscore.js library:

    var data =   [{"Id":1,"Order":1,"IsDone":true,"Text":"abc","Date":"6/14/2014"},{"Id":2,"Order":2,"IsDone":false,"Text":"cde","Date":"6/15/2014"},{"Id":3,"Order":3,"IsDone":false,"Text":"fgh","Date":"6/16/2014"}];

    var allDesiredElements = _.filter(data, function(item) {
      return item.IsDone === true;
    });

//for length use
console.log(allDesiredElements.length);