gatsby-source-prismic/src/lib/normalizeDocumentSubtree.ts

Gatsby source plugin for building websites using Prismic as a data source

import * as prismicT from "@prismicio/types";
import * as RTE from "fp-ts/ReaderTaskEither";
import * as R from "fp-ts/Record";
import * as O from "fp-ts/Option";
import * as A from "fp-ts/Array";
import { pipe } from "fp-ts/function";
import { Stringable } from "gatsby-node-helpers";

import {
	Dependencies,
	PrismicSpecialType,
	TypePathKind,
	UnknownRecord,
} from "../types";

import { getTypePath } from "./getTypePath";
import { createNodeOfType } from "./createNodeOfType";
import { mapRecordIndices } from "./mapRecordIndices";
import { createRemoteFileNode } from "./createRemoteFileNode";
import { PRISMIC_API_IMAGE_FIELDS } from "../constants";
import { removeURLParameter } from "./removeAutoURLParameter";

/**
 * Determines if a value is a record.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is a record, `false` otherwise.
 */
const unknownRecordRefinement = (value: unknown): value is UnknownRecord =>
	typeof value === "object" && value !== null && !Array.isArray(value);

/**
 * Determines if a value is an array of records.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is an array of records, `false` otherwise.
 */
const unknownRecordArrayValueRefinement = (
	value: unknown,
): value is UnknownRecord[] =>
	Array.isArray(value) && value.every(unknownRecordRefinement);

/**
 * Determines if a value is a Prismic document.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is a Prismic document, `false` otherwise.
 */
const documentRefinement = (
	value: unknown,
): value is prismicT.PrismicDocument =>
	unknownRecordRefinement(value) && "first_publication_date" in value;

/**
 * Determines if a value is an Embed field.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is an Embed field, `false` otherwise.
 */
const embedValueRefinement = (value: unknown): value is prismicT.EmbedField =>
	unknownRecordRefinement(value) && "embed_url" in value;

/**
 * Determines if a value is a Slice.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is a Slice, `false` otherwise.
 */
const sliceValueRefinement = (value: unknown): value is prismicT.Slice =>
	unknownRecordRefinement(value) && "slice_type" in value;

/**
 * Determines if a value is a Slice.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is a Slice, `false` otherwise.
 */
const sharedSliceValueRefinement = (
	value: unknown,
): value is prismicT.SharedSlice =>
	sliceValueRefinement(value) && "variation" in value;

/**
 * Determines if a value is a Slice Zone.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is a Slice Zone, `false` otherwise.
 */
const slicesValueRefinement = (value: unknown): value is prismicT.SliceZone =>
	Array.isArray(value) && value.every(sliceValueRefinement);

/**
 * Determines if the value is Stringable (has a `toString()` method).
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is Stringable, `false` otherwise.
 */
const stringableRefinement = (value: unknown): value is Stringable =>
	(typeof value === "boolean" ||
		typeof value === "number" ||
		typeof value === "bigint" ||
		typeof value === "string" ||
		typeof value === "symbol" ||
		typeof value === "function" ||
		typeof value === "object") &&
	value != null &&
	Boolean(value.toString);

/**
 * Determines if a value is a Link field.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is a Link, `false` otherwise.
 */
export const linkValueRefinement = (
	value: unknown,
): value is prismicT.LinkField => {
	return typeof value === "object" && (value === null || "link_type" in value);
};

/**
 * Determines if a value is an Image field.
 *
 * @param value - Value to check.
 *
 * @returns `true` if the value is an Image, `false` otherwise.
 */
export const imageValueRefinement = (
	value: unknown,
): value is prismicT.ImageField => {
	// Unfortunately, we can't check for specific properties here since it's
	// possible for the object to be empty if an image was never set.
	return typeof value === "object" && value !== null;
};

/**
 * Normalizes a record within a Prismic document. It normalizes each field individually.
 *
 * @param path - Path to the record.
 * @param value - The record to normalize.
 *
 * @returns A normalized version of `value`.
 */
const normalizeDocumentRecord = (
	kind: TypePathKind,
	path: string[],
	value: UnknownRecord,
): RTE.ReaderTaskEither<Dependencies, never, UnknownRecord> =>
	pipe(
		RTE.ask<Dependencies>(),
		RTE.chain((deps) =>
			pipe(
				value,
				mapRecordIndices(deps.transformFieldName),
				R.mapWithIndex((prop, propValue) =>
					normalizeDocumentSubtree(kind, [...path, prop], propValue),
				),
				R.sequence(RTE.ApplicativeSeq),
			),
		),
	);

/**
 * Traverses a subtree from a Prismic document and normalizes values as needed.
 * This function may process the subtree recursively.
 *
 * @param path - Path to the subtree.
 * @param value - The subtree to normalize.
 *
 * @returns A normalized version of `value`.
 */
export const normalizeDocumentSubtree = (
	kind: TypePathKind,
	path: string[],
	value: unknown,
): RTE.ReaderTaskEither<Dependencies, never, unknown> =>
	pipe(
		RTE.ask<Dependencies>(),
		RTE.bind("typePath", () => getTypePath(kind, path)),
		RTE.bind("type", (env) => RTE.right(env.typePath.type)),
		RTE.chain((env) => {
			switch (env.typePath.type) {
				case PrismicSpecialType.Document: {
					return pipe(
						value,
						RTE.fromPredicate(
							documentRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.bindTo("value"),
						RTE.bind("dataField", (scope) =>
							!R.isEmpty(scope.value.data)
								? normalizeDocumentRecord(
										TypePathKind.CustomType,
										[...path, "data"],
										scope.value.data,
								  )
								: RTE.right(undefined),
						),
						RTE.chainW((scope) =>
							RTE.right({
								...scope.value,
								data: scope.dataField,
							}),
						),
					);
				}

				case PrismicSpecialType.DocumentData: {
					return pipe(
						value,
						RTE.fromPredicate(
							unknownRecordRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.chainW((value) =>
							normalizeDocumentRecord(TypePathKind.Field, path, value),
						),
					);
				}

				case prismicT.CustomTypeModelFieldType.Group: {
					return pipe(
						value,
						RTE.fromPredicate(
							unknownRecordArrayValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.map(
							A.map((item) =>
								normalizeDocumentRecord(TypePathKind.Field, path, item),
							),
						),
						RTE.chainW(RTE.sequenceArray),
					);
				}

				case prismicT.CustomTypeModelFieldType.Slices: {
					return pipe(
						value,
						RTE.fromPredicate(
							slicesValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.map(
							A.map((item) =>
								sharedSliceValueRefinement(item)
									? normalizeDocumentSubtree(
											TypePathKind.SharedSliceVariation,
											[item.slice_type, item.variation],
											item,
									  )
									: normalizeDocumentSubtree(
											TypePathKind.Field,
											[...path, item.slice_type],
											item,
									  ),
							),
						),
						RTE.chainW(RTE.sequenceArray),
					);
				}

				case prismicT.CustomTypeModelSliceType.Slice: {
					return pipe(
						value,
						RTE.fromPredicate(
							sliceValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.bindTo("value"),
						RTE.bindW("primary", (scope) =>
							normalizeDocumentRecord(
								TypePathKind.Field,
								[...path, "primary"],
								scope.value.primary,
							),
						),
						RTE.bindW("items", (scope) =>
							pipe(
								scope.value.items,
								A.map((item) =>
									normalizeDocumentRecord(
										TypePathKind.Field,
										[...path, "items"],
										item,
									),
								),
								RTE.sequenceArray,
							),
						),
						RTE.map((scope) => ({
							...scope.value,
							primary: scope.primary,
							items: scope.items,
						})),
					);
				}

				case PrismicSpecialType.SharedSliceVariation: {
					return pipe(
						value,
						RTE.fromPredicate(
							sharedSliceValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.bindTo("value"),
						RTE.bindW("primary", (scope) =>
							normalizeDocumentRecord(
								TypePathKind.Field,
								[...path, "primary"],
								scope.value.primary,
							),
						),
						RTE.bindW("items", (scope) =>
							pipe(
								scope.value.items,
								A.map((item) =>
									normalizeDocumentRecord(
										TypePathKind.Field,
										[...path, "items"],
										item,
									),
								),
								RTE.sequenceArray,
							),
						),
						RTE.map((scope) => ({
							...scope.value,
							primary: scope.primary,
							items: scope.items,
						})),
					);
				}

				case prismicT.CustomTypeModelFieldType.Embed: {
					return pipe(
						value,
						RTE.fromPredicate(
							embedValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.bindTo("value"),
						RTE.bind("id", (scope) =>
							pipe(
								R.lookup("embed_url", scope.value),
								RTE.fromOption(
									() => new Error("Embed URL field does not exist"),
								),
								RTE.filterOrElse(
									(url): url is string => typeof url === "string",
									() => new Error("Embed URL field is not a string"),
								),
								RTE.map(env.nodeHelpers.createNodeId),
							),
						),
						RTE.chainW((scope) =>
							// This type name matches the method used in
							// `buildEmbedFieldConfig`.
							createNodeOfType({ ...scope.value, id: scope.id }, "EmbedType"),
						),
						RTE.map((node) => node.id),
						RTE.orElseW(() => RTE.right(null)),
					);
				}

				case prismicT.CustomTypeModelFieldType.IntegrationFields: {
					return pipe(
						value,
						RTE.fromPredicate(
							unknownRecordRefinement,
							() => new Error("Field value is not a plain object"),
						),
						RTE.bindTo("value"),
						RTE.bind("id", (scope) =>
							pipe(
								scope.value,
								R.lookup("id"),
								O.filter(stringableRefinement),
								O.getOrElseW(() => env.createContentDigest(scope.value)),
								(id) => RTE.right(id),
							),
						),
						RTE.chainW((scope) =>
							createNodeOfType({ ...scope.value, id: scope.id }, [
								...path,
								"IntegrationType",
							]),
						),
						RTE.map((node) => node.id),
					);
				}

				case prismicT.CustomTypeModelFieldType.Link: {
					return pipe(
						value,
						RTE.fromPredicate(
							linkValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.bindTo("value"),
						RTE.bind("fileNode", (scope) => {
							return scope.value.link_type == prismicT.LinkType.Media &&
								"url" in scope.value &&
								scope.value.url
								? createRemoteFileNode({
										url: scope.value.url,
										path,
										field: scope.value,
								  })
								: RTE.right(null);
						}),
						RTE.map((scope) => ({
							...scope.value,
							localFile: scope.fileNode?.id || null,
						})),
					);
				}

				case prismicT.CustomTypeModelFieldType.Image: {
					return pipe(
						value,
						RTE.fromPredicate(
							imageValueRefinement,
							() =>
								new Error(
									`Field value does not match the type declared in its type path: ${env.type}`,
								),
						),
						RTE.bindTo("value"),
						RTE.bind("thumbnails", (scope) =>
							pipe(
								scope.value,
								R.filterWithIndex<string, prismicT.ImageFieldImage>(
									(key) => !PRISMIC_API_IMAGE_FIELDS.includes(key),
								),
								RTE.right,
								RTE.bindTo("thumbnails"),
								RTE.bind("thumbnailFileNodes", (thumbnailsScope) =>
									pipe(
										thumbnailsScope.thumbnails,
										R.mapWithIndex((thumbnailName, thumbnail) =>
											thumbnail.url
												? createRemoteFileNode({
														url: removeURLParameter(thumbnail.url, "auto"),
														path: [...path, thumbnailName],
														field: thumbnail,
												  })
												: RTE.right(null),
										),
										R.sequence(RTE.ApplicativeSeq),
									),
								),
								RTE.map((scope) =>
									pipe(
										scope.thumbnails,
										R.mapWithIndex((key, value) => ({
											...value,
											localFile: scope.thumbnailFileNodes[key]?.id || null,
										})),
									),
								),
							),
						),
						RTE.bind("fileNode", (scope) => {
							return scope.value.url
								? createRemoteFileNode({
										url: removeURLParameter(scope.value.url, "auto"),
										path,
										field: scope.value,
								  })
								: RTE.right(null);
						}),
						RTE.map((scope) => ({
							...scope.value,
							...scope.thumbnails,
							localFile: scope.fileNode?.id || null,
						})),
					);
				}

				case prismicT.CustomTypeModelFieldType.Boolean:
				case prismicT.CustomTypeModelFieldType.Color:
				case prismicT.CustomTypeModelFieldType.Date:
				case prismicT.CustomTypeModelFieldType.GeoPoint:
				case prismicT.CustomTypeModelFieldType.Number:
				case prismicT.CustomTypeModelFieldType.Select:
				case prismicT.CustomTypeModelFieldType.StructuredText:
				case prismicT.CustomTypeModelFieldType.Text:
				case prismicT.CustomTypeModelFieldType.Timestamp:
				case prismicT.CustomTypeModelFieldType.UID:
				case PrismicSpecialType.Unknown:
				default: {
					return RTE.throwError(
						new Error("Normalization not necessary for this value."),
					);
				}
			}
		}),
		// If a normalizer fails or no normalizer exists for the subtree, keep the
		// subtree as is.
		RTE.orElse(() => RTE.right(value)),
	);