How to check whether an object key exists or not in JavaScript?

Question

I am getting an object from backend and that object has several keys and values. According to the database data sometimes some of the keys won't be available. So I have used ternary operator for it but still, it is not working.

 `
  <tr>
     <td>
         ${(df[temp].image.status)?df[temp].image.status:'Not Assigned'}
     </td>
  </tr>
  `

Expected result: Whether an "image" key is there or not there shouldn't be any error. Either it should be some status or 'Not Assigned';

Current result: TypeError: df[temp].image is undefined

Anyone any idea why this is happening?

One is image.status and the other says imagestatus. The first one probably has an extra . — adiga
– adiga, Commented May 30, 2019 at 11:58

Ludo · Accepted Answer · 2019-05-30 12:13:02Z

2

You are checking on already undefined value. First you need to verify that image exists and then you can access its fields.

<tr>
    <td>
        ${(df[temp].image && df[temp].image.status) ? (df[temp].image.status) : 'Not Assigned'}
    </td>
</tr>

edited May 30, 2019 at 12:13

answered May 30, 2019 at 12:06

Ludo

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4 Comments

Sweta Sharma Over a year ago

so we cant directly check for df[temp].image.status?

Ludo Over a year ago

@lealceldeiro good point, edited answer to include check also for status field

Ludo Over a year ago

@swetasharma no, you cannot, whenever you try to access status, you need to have image object present already

arizafar Over a year ago

you don't need the ternary here df[temp].image && df[temp].image.status || 'Not Assigned' will also work.

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