isBoolean

Summary

In this lesson we explain how to enforce Boolean values on attributes of type ref or JSON in Sails.js using a validation rule. The example focuses on a hasAgreedToTerms attribute, which represents whether a user has accepted the terms and conditions. By applying the Boolean validation, Sails ensures that only true or false values are accepted, rejecting other data types like strings or numbers. The demonstration shows that while ref stores values as strings internally, the constraint ensures that only Boolean values are allowed.

Transcript

Another Waterline validation rule we can look at is the rule that checks or asserts that an attribute with the data type of ref or json is Boolean.

All right, so maybe you want ref for the data type, but at the current state of the application, you want only Boolean values for that attribute. The way you could do it is to use this validation rule we're going to look at. So let's jump right in.

So right here in our model, in our user model, if we add—let's say, in a standard registration form, we have this checkbox that lets the user click on it if they agree to the terms and policy of the application or website. So let's say you're saving those values as a Boolean, right?

We could do:

hasAgreedToTerms: {
  type: 'ref',
  isBoolean: true
}

Then we could say type is ref, but we want it to be Boolean.

So remember, this works on both ref and JSON attribute types.

Now, if we check out Guppy and run:

await User.create({ hasAgreedToTerms: "someRandomString" });

It should fail, telling us that it's not a Boolean.

How about a number? Would a number pass? No, a number doesn’t pass either.

The only valid values are true or false.

If we do:

await User.create({ hasAgreedToTerms: true });

It passes, and you can see that it saves it as a string because of the ref value.

So in JavaScript, we can parse it for true or false because we know we are expecting a Boolean.

If we do:

await User.create({ hasAgreedToTerms: false });

We see that it forces the string "false" just because it's stored as ref, but we are adding the constraint that we are expecting true or false in both cases.

So that's it! That’s how you can verify that you get a Boolean when using the ref or json attribute types.