how can I prevent errors with nested data in an array if it is empty?

Question

I have this example:

var data={
  city:{
    street:{
      houses:[]
    }
  }
}

alert(data.city.street.houses?.[0].person);

    var data={
      city:{
        street:{
          houses:[]
        }
      }
    }

    alert(data.city.street.houses?.[0].person);

this would show an error because it does not exist houses[0], how can I avoid having errors but in case houses[0] does exist, continue with the nesting?

doing this, I am getting errors:

how can I do it?

I think you put the optional chaining operator in the wrong place. You might have meant to put it after the [0] — MrMythical
– MrMythical, Commented Oct 12, 2021 at 2:53

Spectric · Accepted Answer · 2021-10-12 20:07:39Z

1

Just add another chaining operator after the array item reference:

var data = {
  city: {
    street: {
      houses: []
    }
  }
}

let res = data.city.street.houses?.[0];
res = res != undefined ? res.person : 'no value';
console.log(res);

edited Oct 12, 2021 at 20:07

answered Oct 12, 2021 at 2:56

Spectric

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4 Comments

yavgz Over a year ago

I add some details in my question, can you see again please?

Samathingamajig Over a year ago

@yavgz something is wrong with your IDE if it's giving an error with this answer. Make sure you're on the latest version

yavgz Over a year ago

I know that maybe it is out of the scope of the question, but maybe you know how to help me, I can make a ternary operator in the case that the nesting becomes undefined?

Spectric Over a year ago

@yavgz I've updated my answer.

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