Custom validators ignore return value

I just updated from v5.3.1 to the latest v6.1.1. And I realized my custom validators are not working anymore. I used to just return false; to make the validator fail. But now I need to throw an exception.

To me this would be a “breaking change”, but I couldn’t find anything in the changelog. And another question would be if there is a particular benefit doing it that way? I find it cleaner to just return a boolean, cause that is exactly what one asks the validator: “Can you check if this check is true or false?”

[gustavohenke]

@sheghun people used to complain that a custom validator needed a return value to tag their field valid.

E.g.

check('email').custom(email => findUserByEmail(email).then(user => {
	if (user) {
		throw new Error('email exists');
	}

	return true; // 😐
})

…whereas the docs have always stated (although not clearly) that a resolved promise means a valid field. So the return value shouldn’t be important.

I have expanded the docs with clearer details on this.

[gustavohenke]

Ah yup, when the custom validator is async a resolved promise means a successful result. I guess it needs more extensive docs then.