Schemas

Schemas are an optional description of the structure of a resource type. Defining a schema allows you to use more features of Standard Resource. They also can help you to prevent certain kinds of bugs.

Keep in mind: schemas are entirely optional. You may decide to start using Standard Resource without schemas, and then add them in later. Or maybe you never add them. That is okay.

Defining a Schema

A schema is a JavaScript object. The simplest schema, then, is just an empty object:

{
}

Although an empty object is a valid schema, it isn't particularly useful as it doesn't do anything!

In this guide, we will cover all of the properties of a schema.

Using a Schema

Once you have your schemas defined, you can add it to your store when you create the store using the second argument to createResourceStore(). In this example, we add a few schemas to our store:

import createResourceStore from 'standard-resource';
import books from './schemas/books';
import authors from './schemas/authors';

export default createResourceStore(null, {
  schemas: {
    books,
    authors,
  },
});

You cannot add, change, or remove schemas after the store has been created.

Schema Properties

The rest of this guide will describe the different properties of a schema.

idType

This defines what the data type is of the resource IDs. There are three valid values:

• "string": The ID is a string

• "number": The ID is a number

• ["string", "number"]: The ID can be either a string or a number

By default, the idType is ["string", "number"].

export default {
  idType: 'string',
};

idProperty

The name of the ID property. By default, it is "id".

Sometimes, servers return IDs on a different property, such as "bookId". You have two choices in these situations: rename it to "id", or specify the "idProperty" in the schema.

export default {
  idProperty: 'bookId',
};

attributes

The attributes property allows you to specify the types of the resource's attributes. This can help you to prevent bugs in your app.

For instance, if your resource has a name that should always be a string, then you can specify that here. Then, if you update the state with a name that is something other than a string, you will be warned.

To specify your attribute types, you should use the PropTypes library.

import PropTypes from 'prop-types';

export default {
  attributes: {
    name: PropTypes.string,
    year: PropTypes.number,
  },
};

To take full advantage of the attributes property, we encourage you to familiarize yourself with the PropTypes library by reading its documentation.

meta

This property is identical in structure to attributes, except that it applies to the resource metadata instead.

import PropTypes from 'prop-types';

export default {
  meta: {
    isSelected: PropTypes.bool,
  },
};

computedAttributes

Computed attributes allow you to specify the computed attributes for your resource. We encourage you to read the guide on computed attributes to learn more about them.

In this example, we define a display name that is computed from the first and last name of the resource.

export default {
  computedAttributes: {
    displayName(resource) {
      return `${resource.firstName} ${resource.lastName[0]}`;
    },
  },
};

In this example, we use the Reselect library to memoize a slow computed computed:

import createSelector from 'reselect';

export default {
  computedAttributes: {
    sortedItems: createSelector(
      resource => resource.attributes.items,
      items => sortItemsAlphabetically(items)
    ),
  },
};