minLength

Summary

In Sails.js, use the minLength validation rule to enforce a minimum character length for string attributes. This ensures that values like firstName or password meet a specified length requirement (e.g., at least 2 characters). If the input is shorter than the configured minimum, the validation fails, preventing invalid data from being saved.

Transcript

Oftentimes, you might want to set a minimum length for a string. For example, you may want a string to be at least a specific number of characters long. While you could handle this in your business logic, Sails provides a built-in validation rule called minLength to simplify this process.

Let’s apply this to the firstName attribute. Suppose we want firstName to be at least 2 characters long. Here’s how you can configure it:

firstName: {  
  type: 'string',  
  minLength: 2  
}  

This ensures that firstName must be 2 characters or longer.

Testing the Validation:

1. Invalid Input (Too Short):

   await User.create({ firstName: 'K' });  

   Error: "Value 'K' was shorter than the configured minimum length (2)."

2. Valid Input (Meets Minimum Length):

   await User.create({ firstName: 'Ari' });  

   Result: The record is created successfully.

Use Cases:

• Enforce minimum lengths for attributes like firstName, lastName, or password.

• Ensure data quality by preventing overly short or invalid inputs.

This is how you use the minLength validation rule in Sails to set a lower bound for string attributes.