Validation of empty strings in Zapier JavaScript with alternate value not operational

Other Questions Zapier
1

I am using a webhook in Zapier and I need to check if a certain input is empty. The aim is to verify if NAME1 has any value; if not, I would like to default to using NAME2 instead.

let output = 'Default Name';
if(inputData.NAME1 !== '') {
  output = {name: inputData.NAME1};
} else {
  output = {name: inputData.NAME2};
}
return output;

The logic appears to work during the test phase, yet it encounters issues when the zap is live. The name variable is not being acknowledged in later steps that need it. I’ve experimented with initializing the variable before returning it as well as returning it right in the if statement. What could be causing this issue?

2

Had the exact same issue last month. Zapier’s webhook field mapping gets screwed up when you switch from string to object between test and live runs. It locks onto whatever data structure you use during setup, so changing it later breaks everything.

Here’s what fixed it for me - keep your object structure consistent from the get-go:

let output = {name: 'Default Name'};
if(inputData.NAME1 && inputData.NAME1 !== null && inputData.NAME1 !== '') {
  output = {name: inputData.NAME1};
} else if(inputData.NAME2 && inputData.NAME2 !== null && inputData.NAME2 !== '') {
  output = {name: inputData.NAME2};
}
return output;

Once you make this change, refresh your field mapping in the next steps - Zapier’s cached the broken version. The test environment never shows you the real data types you’ll get in production, which is why this happens.

3

Your logic’s broken - you’re only checking if NAME1 isn’t an empty string, but webhooks can send null, undefined, or just whitespace. Your check misses all of these.

Plus you’re mixing return types. First you return ‘Default Name’ as a string, then objects with name properties. That’ll break whatever comes next.

This is probably what’s happening:

if(inputData.NAME1 !== '') // Fails if NAME1 is null or undefined

You need to catch all empty cases:

if(inputData.NAME1 && inputData.NAME1.trim() !== '')

Honestly though, debugging webhook validation in Zapier’s JavaScript is awful. The test phase never matches real webhook data, so you’re just guessing what’s actually coming through.

I ditched Zapier for Latenode because of this exact problem. It has actual debugging tools where you can see the real data at each step. The conditional logic nodes handle this validation way cleaner without any JavaScript.

In Latenode, you’d just drag a condition node, check if NAME1 exists and isn’t empty, then route to NAME1 or NAME2. No code, and you can see exactly what data triggered which path.

4

That inconsistent return type is your problem right there. You’re starting with a string for output, then switching to objects. Zapier’s step mapping gets confused by this. I’ve hit the same issue before - Zapier’s JavaScript step is wonky with webhook data validation. Test environment shows you one data structure, then production throws something completely different at you. Here’s what works better - stick to the same object structure and beef up your validation:

let finalName = 'Default Name';
if(inputData.NAME1 && typeof inputData.NAME1 === 'string' && inputData.NAME1.trim().length > 0) {
  finalName = inputData.NAME1.trim();
} else if(inputData.NAME2 && typeof inputData.NAME2 === 'string' && inputData.NAME2.trim().length > 0) {
  finalName = inputData.NAME2.trim();
}
return {name: finalName};

This checks if it exists, if it’s actually a string, and if there’s real content in there. The trim() catches those sneaky whitespace-only strings that pass basic empty checks.

5

your mixed return types are breaking Zapier’s field mapping. webhooks send messy data - empty strings, nulls, random spaces. use inputData.NAME1?.trim() to handle those edge cases. keep your object structure consistent or Zapier won’t know what fields to expect.

6

Been there. Zapier’s JavaScript step is a nightmare for webhook validation - you’re flying blind with the data flow. Yeah, everyone’s right about return types, but the real issue is guessing what the webhook actually sends.

Wasted hours debugging this exact problem until I switched to Latenode. Skip the JavaScript headaches and use their Filter node instead - drag and drop conditions you can actually see.

Just set “if NAME1 isn’t empty, use NAME1, otherwise use NAME2” with visual nodes. No debugging code, and you see everything in real time when webhooks fire.

Execution logs show exactly what data triggered which path. You’ll know instantly if NAME1 was null, empty, or just whitespace. Beats Zapier’s black box debugging by miles.