Question

129

Object has-property-deep check in JavaScript

rated 0 times [ 134] [ 5] / answers: 1 / hits: 15337 / 9 Years ago, fri, october 30, 2015, 12:00:00

Let's say we have this JavaScript object:

var object = {

   innerObject:{

       deepObject:{

           value:'Here am I'

       }

   }

};

How can we check if value property exists?

I can see only two ways:

First one:

if(object && object.innerObject && object.innerObject.deepObject && object.innerObject.deepObject.value) {

    console.log('We found it!');

}

Second one:

if(object.hasOwnProperty('innerObject') && object.innerObject.hasOwnProperty('deepObject') && object.innerObject.deepObject.hasOwnProperty('value')) {

    console.log('We found it too!');

}

But is there a way to do a deep check? Let's say, something like:

object['innerObject.deepObject.value']

or

object.hasOwnProperty('innerObject.deepObject.value')

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gregoriocoya

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answered 9 Years ago aidanl · Accepted Answer

There isn't a built-in way for this kind of check, but you can implement it easily. Create a function, pass a string representing the property path, split the path by ., and iterate over this path:

Object.prototype.hasOwnNestedProperty = function(propertyPath) {

  if (!propertyPath)

    return false;



  var properties = propertyPath.split('.');

  var obj = this;



  for (var i = 0; i < properties.length; i++) {

    var prop = properties[i];



    if (!obj || !obj.hasOwnProperty(prop)) {

      return false;

    } else {

      obj = obj[prop];

    }

  }



  return true;

};



// Usage:

var obj = {

  innerObject: {

    deepObject: {

      value: 'Here am I'

    }

  }

}



console.log(obj.hasOwnNestedProperty('innerObject.deepObject.value'));