CODEWITHSUNDEEP
javascriptjson
Babis.amas
Babis.amas

Reputation: 471

Json iteration fails when there is one sub object

I'm converting an xml string to json using php and then posting it to a javascript file where I try to iterate it. When the object contains more than one object, json contains an array of objects like the first sample and I can iterate using the .length function but when the object contains only 1 object an array is not being created and the .length function fails. How can I make the iteration work in both cases without knowing the object's name?

Sample 1:

{"class":[
   {
      "name":"history",
      "grade":"10"
   },
   {
      "name":"chemistry",
      "grade":"8"
   }
  ]
}

Sample 2:

{"class":
   {
      "name":"history",
      "grade":"10"
   }
}

Upvotes: 0

Views: 38

Answers (4)

Danil Speransky
Danil Speransky

Reputation: 30473

You could check length, and if it's undefined it means it's just an object, then you make it an array with just one element:

if collection.length == undefined:
  collection = [collection]

# the rest of the code doesn't need to be changed

Upvotes: 1

Josh
Josh

Reputation: 1484

You have to know the data type of the variable before knowing how to use .length properly. 

var dataTypeLength;
var data = {
 "class":
   {
     "name":"history",
     "grade":"10"
   }
}

if (Array.isArray(data.class)) {
  dataTypeLength = data.class.length;
} else {
  dataTypeLength = Object.keys(data.class).length;
}

console.log(dataTypeLength);

Upvotes: 1

AJ X.
AJ X.

Reputation: 2770

You can check to see if the object is an array first: Array.isArray(obj) . If it isn't then you know you don't need to iterate it.

var obj = {"class":[
   {
      "name":"history",
      "grade":"10"
   },
   {
      "name":"chemistry",
      "grade":"8"
   }
  ]
}

if (!Array.isArray(obj)) return obj;
// else iterate it.

Upvotes: 1

Edison Biba
Edison Biba

Reputation: 4443

You can use for for that and you don't need length

var test = {"class":[
   {
      "name":"history",
      "grade":"10"
   },
   {
      "name":"chemistry",
      "grade":"8"
   }
  ]
}

for (var i in test){
    console.log(test[i]);
}

Upvotes: 1

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