Defining Keystone.js Fields: A Comprehensive Guide

Keystone.js is a powerful Node.js framework for building database-driven applications. One of its key features is the ability to define custom fields for your models. In this article, we'll explore how to define Keystone.js fields and provide examples to help you get started.

Understanding Keystone.js Fields

Keystone.js fields are used to define the structure of your data models. Each field represents a single piece of data that can be stored in your database. Keystone.js provides a range of built-in field types, including text, number, date, and more.

Keystone.js Field Types

Keystone.js provides the following field types:

• Text: A text field for storing short strings of text.
• Text Area: A text area field for storing longer strings of text.
• Number: A number field for storing numeric values.
• Date: A date field for storing dates and times.
• Boolean: A boolean field for storing true or false values.
• Relationship: A relationship field for linking to other models.
• Select: A select field for storing a value from a predefined list.
• Checkbox: A checkbox field for storing a boolean value.

Defining Keystone.js Fields

To define a Keystone.js field, you'll need to create a new instance of the `Keystone.Field` class and pass in the field type and any additional options.

const { Keystone } = require('@keystonejs/keystone');

const keystone = new Keystone({
  // ...
});

keystone.createList('User', {
  fields: {
    name: { type: Text },
    email: { type: Text },
    isAdmin: { type: Boolean },
  },
});

Field Options

Each field type has its own set of options that can be used to customize its behavior. For example, the `Text` field type has an `isUnique` option that can be used to ensure that each value is unique.

keystone.createList('User', {
  fields: {
    email: { type: Text, isUnique: true },
  },
});

Custom Field Types

Keystone.js also allows you to define custom field types. To do this, you'll need to create a new class that extends the `Keystone.Field` class and implements the `getAdminMeta` and `getAdminUI` methods.

class CustomFieldType extends Keystone.Field {
  getAdminMeta() {
    return {
      label: 'Custom Field',
      description: 'A custom field type',
    };
  }

  getAdminUI() {
    return {
      component: 'CustomFieldUI',
      props: {
        // ...
      },
    };
  }
}

keystone.createList('User', {
  fields: {
    customField: { type: CustomFieldType },
  },
});

Conclusion

Defining Keystone.js fields is a crucial part of building database-driven applications with Keystone.js. By understanding the different field types and options available, you can create custom fields that meet the needs of your application.

Frequently Asked Questions

Q: What is the difference between a Text field and a Text Area field?

A: A Text field is used for storing short strings of text, while a Text Area field is used for storing longer strings of text.

Q: How do I define a custom field type?

A: To define a custom field type, you'll need to create a new class that extends the `Keystone.Field` class and implements the `getAdminMeta` and `getAdminUI` methods.

Q: Can I use a custom field type in a Keystone.js list?

A: Yes, you can use a custom field type in a Keystone.js list by passing an instance of the custom field type to the `fields` option when creating the list.

Q: How do I ensure that each value in a Text field is unique?

A: You can ensure that each value in a Text field is unique by setting the `isUnique` option to `true` when defining the field.

Q: Can I use a Relationship field to link to another model?

A: Yes, you can use a Relationship field to link to another model by passing the name of the model to the `ref` option when defining the field.