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Sanity Studio Schema Types

Content modelling

• Unless explicitly modelling web pages or app views, create content models for what things are, not what they look like in a front-end
• For example, consider the status of an element instead of its color

Basic schema types

• ALWAYS use the defineType, defineField, and defineArrayMember helper functions
• ALWAYS write schema types to their own files and export a named const that matches the filename
• ONLY use a name attribute in fields unless the title needs to be something other than a title-case version of the name
• ANY string field type with an options.list array with fewer than 5 options must use options.layout: "radio"
• ANY image field must include options.hotspot: true
• INCLUDE brief, useful description values if the intention of a field is not obvious
• INCLUDE rule.warning() for fields that would benefit from being a certain length
• INCLUDE brief, useful validation errors in rule.required().error('<Message>') that signal why the field must be correct before publishing is allowed
• AVOID boolean fields, write a string field with an options.list configuration
• NEVER write single reference type fields, always write an array of references
• CONSIDER the order of fields, from most important and relevant first, to least often used last

// ./src/schemaTypes/lessonType.ts

import {defineField, defineType} from 'sanity'

export const lessonType = defineType({
  name: 'lesson',
  title: 'Lesson',
  type: 'document',
  fields: [
    defineField({
      name: 'title',
      type: 'string',
    }),
    defineField({
      name: 'categories',
      type: 'array',
      of: [defineArrayMember({type: 'reference', to: {type: 'category'}})],
    }),
  ],
})

Schema type with custom input components

• If a schema type has input components, they should be colocated with the schema type file. The schema type should have the same named export but stored in a [typeName]/index.ts file:

// ./src/schemaTypes/seoType/index.ts

import {defineField, defineType} from 'sanity'

import seoInput from './seoInput'

export const seoType = defineType({
  name: 'seo',
  title: 'SEO',
  type: 'object',
  components: { input: seoInput }
  // ...
})

No anonymous reusable schema types

• ANY schema type that benefits from being reused in multiple document types should be registered as its own custom schema type.

// ./src/schemaTypes/blockContentType.ts

import {defineField, defineType} from 'sanity'

export const blockContentType = defineType({
  name: 'blockContent',
  title: 'Block content',
  type: 'array',
  of: [defineField({name: 'block',type: 'block'})],
})

Decorating schema types

Every document and object schema type should:

• Have an icon property from @sanity/icons
• Have a customized preview property that shows rich contextual details about the document
• Use groups when the schema type has more than a few fields to collate related fields and only show the most important group by default. These groups should use the icon property as well.
• Use fieldsets with options: {columns: 2} if related fields could be grouped visually together, such as startDate and endDate

Writing Sanity content for importing

When asked to write content:

• ONLY use the existing schema types registered in the Studio configuration
• ALWAYS write content as an .ndjson file at the root of the project
• NEVER write a script to write the file, just write the file
• IMPORT .ndjson files using the CLI command npx sanity dataset import <filename.ndjson>
• NEVER include a . in the _id field of a document unless you need it to be private
• NEVER include image references because you don't know what image documents exist
• ALWAYS write images in this format below, replacing the document ID value to generate the same placeholder image

{"_type":"image","_sanityAsset":"image@[https://picsum.photos/seed/](https://picsum.photos/seed/)[[REPLACE_WITH_DOCUMENT_ID]]/1920/1080"}

Writing GROQ queries

• ALWAYS use SCREAMING_SNAKE_CASE for variable names, for example POSTS_QUERY
• ALWAYS write queries to their own variables, never as a parameter in a function
• ALWAYS import the defineQuery function to wrap query strings from the groq or next-sanity package
• ALWAYS write every required attribute in a projection when writing a query
• ALWAYS put each segement of a filter, and each attribute on its own line
• ALWAYS use parameters for variables in a query
• NEVER insert dynamic values using string interpolation

Here is an example of a good query:

import {defineQuery} from 'groq'

export const POST_QUERY = defineQuery(`*[
  _type == "post"
  && slug.current == $slug
][0]{
  _id,
  title,
  image,
  author->{
    _id,
    name
  }
}`)

TypeScript generation

For the Studio

• ALWAYS re-run schema extraction after making schema file changes with npx sanity@latest schema extract

For monorepos with a studio and a front-end

• ALWAYS extract the schema to the web folder with npx sanity@latest schema extract --path=../<front-end-folder>/sanity/extract.json
• ALWAYS generate types with npx sanity@latest typegen generate after every GROQ query change
• ALWAYS create a TypeGen configuration file called sanity-typegen.json at the root of the front-end code-base

{
  "path": "./**/*.{ts,tsx,js,jsx}",
  "schema": "./<front-end-folder>/sanity/extract.json",
  "generates": "./<web-folder>/sanity/types.ts"
}

For the front-end

• ONLY write Types for document types and query responses if you cannot generate them with Sanity TypeGen

Project settings and data

• ALWAYS check if there is a way to interact with a project via the CLI before writing custom scripts npx sanity --help