How can i find the total number of keys if the Object is inside an array [duplicate]

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How to efficiently c开发者_如何转开发ount the number of keys/properties of an object in JavaScript?

var array = [{key:value,key:value}]

How can i find the total number of keys if it's an array of Object. When i do check the length of the array, it gives me one.

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If you want to know the number of unique properties of Objects in an Array, this should do it...

var uniqueProperties = [];

for (var i = 0, length = arr.length; i < length; i++) {
   for (var prop in arr[i]) {
       if (arr[i].hasOwnProperty(prop) 
           && uniqueProperties.indexOf(prop) === -1
          ) {
          uniqueProperties.push(prop);
       }
   } 
}

var uniquePropertiesLength = uniqueProperties.length;

jsFiddle.

Note that an Array's indexOf() doesn't have the best browser support. You can always augment the Array prototype (though for safety I'd make it part of a util object or similar).

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If the array will only have one object, array[0] represents the object.

If there's more than one object, you'll need to decide what exactly you want to count.