Robust Validator

How to Validate Nested Objects in JavaScript with Robust Validator ​

Intro ​

When you're working with forms or APIs in JavaScript, you often deal with data that's nested. For example, a user profile might have contact info inside it, and each field needs to be validated.

If you've ever tried to manually check user.contact.email or settings.preferences.notifications, you know how messy it can get.

In this post, you'll learn how to validate nested objects easily using Robust Validator, a simple and powerful validation library inspired by Laravel.

Why Nested Validation Matters ​

Most real-world apps deal with nested data. Things like:

  • User profiles
  • Signup forms
  • JSON payloads for APIs

If you skip validation or only check top-level fields, bugs and bad data will sneak in. That leads to broken features, support tickets, and angry users. Not fun.

Step 1: Install Robust Validator ​

First, install the package:

bash
npm install --save robust-validator

Then import the validator like this:

ts
import { validate } from "robust-validator";

Step 2: Example Data ​

Here's a sample data object you might get from a form or API:

ts
const data = {
  user: {
    name: "Alice",
    contact: {
      email: "alice@example.com",
      phone: "",
    },
  },
};

Now let’s say we want to check:

  • user.name is required and should be at least 3 characters
  • user.contact.email is required and should be a valid email
  • user.contact.phone is required

Step 3: Write the Schema ​

Robust Validator supports dot notation for nested fields.

Option 1: String-based rules ​

ts
const schema = {
  "user.name": "required|min:3",
  "user.contact.email": "required|email",
  "user.contact.phone": "required",
};

Option 2: Function-based rules ​

ts
import { required, min, email } from "robust-validator";

const schema = {
  "user.name": [required(), min(3)],
  "user.contact.email": [required(), email()],
  "user.contact.phone": [required()],
};

Both ways work the same. Pick the one you like better.

Step 4: Run the Validation ​

Here’s how you validate the data:

ts
const result = validate(data, schema);

if (!result.passes()) {
  console.log(result.errors());
}

Example Output ​

If user.contact.phone is empty, you’ll get this:

json
{
  "isValid": false,
  "isInvalid": true,
  "fields": {
    "user.name": true,
    "user.contact.email": true,
    "user.contact.phone": false
  },
  "errors": {
    "user.contact.phone": [
      { "rule": "required", "message": "The field is required." }
    ]
  }
}

Now you can show this message to the user or send it back in an API response.

When to Use This ​

Use this approach anytime you’re validating:

  • Form inputs with nested data
  • API request bodies
  • Config or settings objects

Basically, anytime your object isn’t flat.

Wrap-Up ​

Nested object validation doesn’t have to be complicated. With Robust Validator, you can write clear, simple rules using dot notation. It handles the hard parts so you can focus on building your app.

Give it a try and make your validation cleaner and more reliable.