Extracting the last item from a nested array in JavaScript (AirTable Scripting)

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1

I’m new to JavaScript and working on an AirTable project. I’m trying to get info from an API and update my table. The tricky part is getting the most recent vote data.

Here’s what I’ve got so far:

let apiToken = 'my_secret_token'
let table = base.getTable('Bill Info')
let { records } = await table.selectRecordsAsync()

for (let record of records) {
  let response = await remoteFetchAsync(`https://api.example.com/bills/${record.id}?key=${apiToken}`)
  let data = await response.json()
  console.log(data.bill)

  // This part isn't working
  const lastVote = data(data.votes.length - 1)
}

I’m stuck on two things:

  1. How do I correctly set the lastVote variable? I tried using length - 1 but it’s not right.
  2. Is there a better way to get the last item in an array?

When I run this, I get an error:

TypeError: Cannot read properties of undefined (reading 'length')

Any tips would be awesome! I’m more used to R, so JavaScript is still new to me.

2

As someone who’s worked extensively with AirTable and API integrations, I can offer some insights. Your issue likely stems from how you’re accessing the ‘votes’ property. JavaScript is finicky with undefined values, so we need to be cautious.

A robust approach I’ve found effective is using the optional chaining operator (?.) combined with the nullish coalescing operator (??). It’s clean and handles edge cases well:

const lastVote = data?.votes?.at(-1) ?? null;

This elegantly retrieves the last vote if it exists, or defaults to null. It’s concise and less error-prone than traditional methods.

Also, don’t forget to wrap your API calls in try-catch blocks. APIs can be unpredictable, and error handling will save you headaches down the line. Keep at it – you’re on the right track!

3

hey john, i’ve dealt with similar stuff. looks like data.votes might be undefined. try this:

const lastVote = data.votes && data.votes.length ? data.votes[data.votes.length - 1] : null;

this checks if votes exist and have length before grabbing the last one. hope it helps!

4

I’ve encountered similar challenges with API data. Your approach is on the right track, but there are a couple of improvements we can make. First, ensure that ‘data.votes’ exists and is an array. Then, you can use the more concise array indexing method to access the last element:

const lastVote = Array.isArray(data.votes) && data.votes.length > 0 ? data.votes[data.votes.length - 1] : null;

Alternatively, for a more modern approach, consider using the optional chaining operator (?.) along with the nullish coalescing operator (??):

const lastVote = data.votes?.at(-1) ?? null;

This method is cleaner and handles potential undefined values gracefully. Remember to add error handling for your API calls to manage unexpected responses effectively.