react native json response check if string or object

Question

sorry for the silly question. I am relatively new to react native. I have got fetch working so I can get the json response back from the server. The server API returns a string if there is an error or returns an json object if its successful. is there any way to compare the response to see if its a string or json variable?

Not sure how to achieve the above any help would be appreciated.

here is my code

API.js

var API = {

   SetupBuyOnline(email, serialNumber, platformType) {
        var url = 'https://<urlomitted>/SetupBuyOnline';
        return fetch(url, {
            method: 'GET',
            headers: {
                'Content-Type': 'application/json; charset=UTF-8',
                'Accept': 'application/json',
                'operating_system': platformType,
                'email': email,
                'serialNumber': serialNumber
            }
        }).then((res) => res.json());
    }
};

find userScreen.js

  findUserScreen(){
    // this.props.navigation.navigate('JoinNowScreen')
    StudentApi.SetupBuyOnline('[email protected]', deviceId, "iOS")
    .then((responseData) => {
      if(typeof(responseData) == 'string')
      {
        console.log('got api call ' + responseData);
        alert('test = ' + responseData);
      }
      else
      {
        console.log('got api call ' + responseData);
        alert(responseData);
      }
    })
  }

Not sure what I am doing wrong. Thanks in advance

Maxime · Accepted Answer · 2019-01-09 15:04:57Z

5

Other than changing your == for === (strict equality) not much. But will work with normal equality.

Dont know what you're doing wrong, because this code works just fine.

What I would do instead is having a JSON response like so:

"{
    error: true,
}"


"{
    error: false,
    data: yourDataSentByTheServer!
}"

That way you only need to check if there's an error property inside your JSON response.

function stringType(){
  const responseData = 'hello';
  if(typeof(responseData) === 'string')
  {
    console.log('got api call ' + responseData);
    alert('test = ' + responseData);
  }
  else
  {
    console.log('got api call ' + responseData);
    alert(responseData);
  }
}

function objType(){
  const responseData = { 1:'hello', 2: 'koko' }
  if(typeof(responseData) === 'string')
  {
    console.log('got api call ' + responseData);
    alert('test = ' + responseData);
  }
  else
  {
    console.log('got api call ' + responseData);
    alert(responseData);
  }
}

<button onClick="stringType();">Click me for string</button>
<button onClick="objType();">Click me for obj</button>

edited Jan 9, 2019 at 15:04

Maxime

9,0695 gold badges53 silver badges54 bronze badges

answered Oct 16, 2017 at 1:47

WilomGfx

2,0221 gold badge20 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

dogwasstar Over a year ago

weird. when I tried before it didnt detect it as a string. Anyway thanks for your help :)

WilomGfx Over a year ago

Alright :) but consider my option for your JSON, its a good approach to keep things concise :)

Collectives™ on Stack Overflow

react native json response check if string or object

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related