gatsby-node.js

/** GraphQL type name for union of all known paragraph types. */
const PARAGRAPH_UNON_NAME = 'paragraph_types_union'

/** GraphQL type name for union of all known media types. */
const MEDIA_UNON_NAME = 'media_types_union'

/** Construct field schema with type overrides. */
function createCustomFields(fields) {
	return fields.reduce((schema, { type, name: fieldName }) => {
		const resolveById = (parent, args, context) => {
			const ids = parent[`${fieldName}___NODE`]

			return context.nodeModel.getNodesByIds({
				ids: Array.isArray(ids) ? ids : [ids]
			})
		}

		switch (type) {
			case 'paragraphs':
				schema[fieldName] = {
					type: `[${PARAGRAPH_UNON_NAME}]`,
					// Resolve correct paragraph nodes.
					resolve: resolveById
				}
				break

			case 'media':
				schema[fieldName] = {
					type: `[${MEDIA_UNON_NAME}]`,
					// Resolve correct media nodes.
					resolve: resolveById
				}

				break
		}

		return schema
	}, {})
}

/**
 * gatsby-source-drupal does not handle GraphQL type unions well if not relationship data is present.
 *
 * For example instead of infering a separate type for each paragraph field it
 * would be easier to reuse code if we had a global paragrah type that
 * would include all paragraph types.
 *
 * This schema customization overrides media and paragraph field types to do
 * just that.
 */
exports.createSchemaCustomization = ({ actions, schema, getNodesByType }) => {
	/** Fix union types for these types and their fields. */
	const FixTypes = [
		{ type: 'node__landing_page', fields: [{ type: 'paragraphs', name: 'field_landing_paragraphs' }] },
		{ type: 'paragraph__hero_form', fields: [{ type: 'media', name: 'field_media_any' }] },
		{ type: 'paragraph__media', fields: [{ type: 'media', name: 'field_media_any' }] }
	]

	const getAllDrupalTypes = drupalType =>
		getNodesByType(drupalType)
			.flatMap(node => Object.keys(node.relationships))
			.map(type => type.replace('___NODE', ''))

	/** Get GraphQL relationship field type name for given type. */
	const relationshipName = type => `${type}__relationship`

	// Get all media types.
	const mediaTypes = getAllDrupalTypes('media_type__media_type')

	// Get all paragrah types (related to any node in any language).
	const paragraphTypes = getAllDrupalTypes('paragraphs_type__paragraphs_type')

	if (process.env.NODE_ENV === 'development') {
		console.log(`Found ${mediaTypes.length} media types:`, mediaTypes)
		console.log(`Found ${paragraphTypes.length} paragraph types:`, paragraphTypes)
	}

	const { createTypes } = actions

	createTypes([
		// Create GraphQL union type that includes all found paragraph types.
		schema.buildUnionType({
			name: PARAGRAPH_UNON_NAME,
			types: paragraphTypes
		}),
		// Create GraphQL union type that includes all media types.
		schema.buildUnionType({
			name: MEDIA_UNON_NAME,
			types: mediaTypes
		}),
		// Override relationship field type for specified content types.
		...FixTypes.map(
			({ type }) => `
				type ${type} implements Node @infer {
					relationships: ${relationshipName(type)}
				}
			`
		),
		// Change relationship field type to include all found paragraphs types.
		...FixTypes.map(({ type, fields }) =>
			schema.buildObjectType({
				name: relationshipName(type),
				interfaces: ['Node'],
				fields: createCustomFields(fields)
			})
		)
	])
}