Question

-2

Count particular key value from array of object

rated 0 times [ 5] [ 7] / answers: 1 / hits: 18826 / 8 Years ago, mon, august 1, 2016, 12:00:00

I have following JSON array I want to create object form status key count

[

  {

    id: 65:0,    

    status: ORANGE

  },

  {

    id: 65:0,

    status: GREEN

  },

  {

    id: 65:0,

    status: ORANGE

  },

  {

    id: 65:0,

    status: YELLOW

  },

  {

    id: 65:0,

    status: RED

  },

  {

    id: 65:0,

    status: GREEN

  },

  {

    id: 65:0,

    status: GREEN

  },

   {

    id: 65:0,

    status: ORANGE

  },

  {

    id: 65:0,

    status: YELLOW

  },

  {

    id: 65:0,

    status: GREEN

  }

]

Want to count status key value and create the following Object

{

 'ORANGE' : 3,

 'GREEN' : 4,

 'YELLOW' : 2,

 'RED' : 1,

}

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harrisonnelsonb

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2 Years ago

answered 8 Years ago micayla · Accepted Answer

Use Array#reduce method

var res = data.reduce(function(obj, v) {

  // increment or set the property

  // `(obj[v.status] || 0)` returns the property value if defined

  // or 0 ( since `undefined` is a falsy value

  obj[v.status] = (obj[v.status] || 0) + 1;

  // return the updated object

  return obj;

  // set the initial value as an object

}, {})

var data = [{

  id: 65:0,

  status: ORANGE

}, {

  id: 65:0,

  status: GREEN

}, {

  id: 65:0,

  status: ORANGE

}, {

  id: 65:0,

  status: YELLOW

}, {

  id: 65:0,

  status: RED

}, {

  id: 65:0,

  status: GREEN

}, {

  id: 65:0,

  status: GREEN

}, {

  id: 65:0,

  status: ORANGE

}, {

  id: 65:0,

  status: YELLOW

}, {

  id: 65:0,

  status: GREEN

}];



var res = data.reduce(function(obj, v) {

  obj[v.status] = (obj[v.status] || 0) + 1;

  return obj;

}, {})



console.log(res);

Although you can use Array#forEach method with the same code.

var res = {};

data.forEach(function(v) {

  res[v.status] = (res[v.status] || 0) + 1;

})

var data = [{

  id: 65:0,

  status: ORANGE

}, {

  id: 65:0,

  status: GREEN

}, {

  id: 65:0,

  status: ORANGE

}, {

  id: 65:0,

  status: YELLOW

}, {

  id: 65:0,

  status: RED

}, {

  id: 65:0,

  status: GREEN

}, {

  id: 65:0,

  status: GREEN

}, {

  id: 65:0,

  status: ORANGE

}, {

  id: 65:0,

  status: YELLOW

}, {

  id: 65:0,

  status: GREEN

}];



var res = {};

data.forEach(function(v) {

  res[v.status] = (res[v.status] || 0) + 1;

})



console.log(res);