Some properties are missing from API's returned data, need solid way to check property

Question

I'm aware that api team is the one responsible for sending correct data to the client that requested the data. However, I still would like to know the best way of checking if property exists or not.

// when state property is missing from the api response
myObject = {
  name : 'Scott',
  addressInfo : {
    address1 : '444 St Peter St',
    address2 : 'Apartment D',
    zipCode  : '55555'
  },
  birthDate : '20000101'
}

or

// or when birtdate is missing
myObject = {
  name : 'Scott',
  addressInfo : {
    address1 : '444 St Peter St',
    address2 : 'Apartment D',
    zipCode  : '55555',
    state    : 'MN'
  }
}

or

// when addressInfo is missing
myObject = {
  name : 'Scott',
  birthDate : '20000101'
}

Is the code below enough for the checking?

if (myObject.addressInfo !== undefined && myObject.addressInfo.state !== undefined) {

    // console.log(
}

`if (myObject.addressInfo) ...` returns a boolean, so if it's not on the object it returns false; no need to do a further check for `myObject.addressInfo.state` if the parent doesn't exist. — Data, Aug 29 '15 at 03:19

guest271314 · Answer 1 · 2015-08-29T03:21:56.003

1

state value could be set as undefined though still be a property of myObject ; try utilizing Object.hasOwnProperty(property)

var myObject = {
  name : 'Scott',
  addressInfo : {
    address1 : '444 St Peter St',
    address2 : 'Apartment D',
    zipCode  : '55555'
  },
  birthDate : '20000101'
};

console.log(myObject.addressInfo.hasOwnProperty("state"))

edited Aug 29 '15 at 03:21

answered Aug 29 '15 at 03:16

guest271314

1
15
104
177

score 1 · Accepted Answer · answered Aug 29 '15 at 03:27

1

If you are willing to use a library like lodash or underscore, then a very convenient way to test if a key is present in an object is the _.has method:

var x = { "a": 1 };
_.has(x,"a"); //returns true
_.has(x,"b"); //returns false

answered Aug 29 '15 at 03:27

zayquan

7,544
2
30
39

using _.has(), how will you check state property? Like this? _.has(myObject, 'addressInfo.state') – devwannabe Aug 29 '15 at 03:39
Like this : `_.has(myObject.addressInfo, 'state')`. In your case myObject.addressInfo is the object being inspected, and 'state' is the key that you are checking. – zayquan Aug 29 '15 at 03:42

score 0 · Answer 3 · edited May 23 '17 at 11:43

0

Right way to check proerty exists:

if(myObj.hasOwnProperty(myProp)){
    alert("yes, i have that property");
}

and

if(myProp in myObj){
    alert("yes, i have that property");
}

From answer: check if object property exists - using a variable

edited May 23 '17 at 11:43

Community

1
1

answered Aug 29 '15 at 03:17

Roman Kirillov

105
14

Some properties are missing from API's returned data, need solid way to check property

3 Answers3