min

Summary

In Sails.js, use the min validation rule to enforce a minimum value for attributes with the number data type. For example, setting min: 18 ensures that the age attribute must be 18 or higher. This prevents invalid inputs (e.g., 0 or 2) while allowing valid values (e.g., 18, 19). However, this rule does not restrict maximum values, which will be addressed in the next lesson.

Transcript

Let’s explore another validation rule: min, which sets a minimum value for attributes with the number data type.

For example, in the User model, we want the age attribute to accept only values of 18 or higher. While we’ve set a default value of 18, this only applies when age is unspecified. Without validation, a user could input invalid values like 0.

To enforce this, add the min property:

age: {  
  type: 'number',  
  defaultsTo: 18,  
  min: 18  
}  

This ensures age must be 18 or higher.

Testing the Validation:

1. Invalid input (e.g., 0 or 2):

   await User.create({ age: 0 });  

   Error: "Value 0 was less than the configured minimum (18)."

2. Valid input (e.g., 18 or 19):

   await User.create({ age: 18 });  
   await User.create({ age: 19 });  

   Result: Records are created successfully.

Limitation:
The min rule does not restrict maximum values (e.g., 2000). We’ll address this in the next lesson using the max validation rule.

Key takeaways:

• Use min to enforce a minimum value for number attributes.

• Combine with defaultsTo for default values when the field is unspecified.

• Stay tuned for the next lesson on enforcing maximum values with max.