refactor(services, types): reorganize GraphQL fetchers and data types

The Typescript mapped types was useful for autocompletion in fetchers
but their are harder to maintain. I think it's better to keep each
query close to its fetcher to have a better understanding of the
fetched data. So I:
* colocate queries with their own fetcher
* colocate mutations with their own mutator
* remove Typescript mapped types for queries and mutations
* move data convertors inside graphql services
* rename most of data types and fetchers

15 files changed, 770 insertions, 0 deletions

diff --git a/src/services/graphql/helpers/build-comments-tree.test.ts b/src/services/graphql/helpers/build-comments-tree.test.ts
new file mode 100644
index 0000000..cd9fa40
--- /dev/null
+++ b/src/services/graphql/helpers/build-comments-tree.test.ts
@@ -0,0 +1,67 @@
+import { describe, expect, it } from '@jest/globals';
+import type { SingleComment } from '../../../types';
+import { buildCommentsTree } from './build-comments-tree';
+
+describe('build-comments-tree', () => {
+  it('transforms a flat comments array to a comments tree', () => {
+    const firstComment = {
+      content: 'Non non provident mollitia a.',
+      id: 1,
+      isApproved: true,
+      meta: { author: { name: 'Emma_Muller' }, date: '2022-11-02' },
+      replies: [],
+    } satisfies SingleComment;
+    const firstCommentReplies = [
+      {
+        content: 'Et omnis voluptatem est atque.',
+        id: 3,
+        isApproved: true,
+        meta: { author: { name: 'Patrick.Goodwin44' }, date: '2022-11-05' },
+        replies: [],
+        parentId: 1,
+      },
+    ] satisfies SingleComment[];
+    const secondComment = {
+      content: 'Vero iure architecto modi iusto qui.',
+      id: 2,
+      isApproved: true,
+      meta: { author: { name: 'Dominique13' }, date: '2022-11-04' },
+      replies: [],
+    } satisfies SingleComment;
+    const secondCommentReplies = [
+      {
+        content: 'Qui quaerat quas quia praesentium quasi.',
+        id: 4,
+        isApproved: true,
+        meta: { author: { name: 'Patrick.Goodwin44' }, date: '2022-11-05' },
+        replies: [],
+        parentId: 2,
+      },
+      {
+        content: 'Ut officia aliquid harum voluptas molestiae quo.',
+        id: 5,
+        isApproved: true,
+        meta: { author: { name: 'Ariel.Braun6' }, date: '2022-11-06' },
+        replies: [],
+        parentId: 2,
+      },
+    ] satisfies SingleComment[];
+    const comments: SingleComment[] = [
+      firstComment,
+      secondComment,
+      ...firstCommentReplies,
+      ...secondCommentReplies,
+    ];
+    const result = buildCommentsTree(comments);
+
+    expect(result).toHaveLength(2);
+    expect(result[0]).toStrictEqual({
+      ...firstComment,
+      replies: firstCommentReplies,
+    });
+    expect(result[1]).toStrictEqual({
+      ...secondComment,
+      replies: secondCommentReplies,
+    });
+  });
+});
diff --git a/src/services/graphql/helpers/build-comments-tree.ts b/src/services/graphql/helpers/build-comments-tree.ts
new file mode 100644
index 0000000..1534cfe
--- /dev/null
+++ b/src/services/graphql/helpers/build-comments-tree.ts
@@ -0,0 +1,30 @@
+import type { SingleComment } from '../../../types';
+
+/**
+ * Create a comments tree with replies.
+ *
+ * @param {SingleComment[]} comments - A flatten comments list.
+ * @returns {SingleComment[]} An array of comments with replies.
+ */
+export const buildCommentsTree = (
+  comments: SingleComment[]
+): SingleComment[] => {
+  type CommentsHashTable = Record<string, SingleComment>;
+
+  const hashTable: CommentsHashTable = Object.create(null);
+  const commentsTree: SingleComment[] = [];
+
+  comments.forEach((comment) => {
+    hashTable[comment.id] = { ...comment, replies: [] };
+  });
+
+  comments.forEach((comment) => {
+    if (comment.parentId) {
+      hashTable[comment.parentId].replies.push(hashTable[comment.id]);
+    } else {
+      commentsTree.push(hashTable[comment.id]);
+    }
+  });
+
+  return commentsTree;
+};
diff --git a/src/services/graphql/helpers/convert-post-preview-to-article-preview.test.ts b/src/services/graphql/helpers/convert-post-preview-to-article-preview.test.ts
new file mode 100644
index 0000000..c13684f
--- /dev/null
+++ b/src/services/graphql/helpers/convert-post-preview-to-article-preview.test.ts
@@ -0,0 +1,130 @@
+import { describe, expect, it } from '@jest/globals';
+import type { WPPostPreview, WPThematicPreview } from '../../../types';
+import { convertPostPreviewToArticlePreview } from './convert-post-preview-to-article-preview';
+import { convertTaxonomyToPageLink } from './convert-taxonomy-to-page-link';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+describe('convert-post-preview-to-article-preview', () => {
+  /* eslint-disable max-statements */
+  it('converts a RecentWPPost object to a RecentArticle object', () => {
+    const post: WPPostPreview = {
+      acfPosts: null,
+      commentCount: 6,
+      contentParts: {
+        beforeMore:
+          'Et quos fuga molestias. Voluptatum nobis mollitia eaque dolorem sunt. Dolores dignissimos consequuntur mollitia. Enim molestias quibusdam sequi. Dolore ut quo. Libero iure non vel reprehenderit.',
+      },
+      databaseId: 5,
+      date: '2021-04-28',
+      featuredImage: null,
+      info: {
+        wordsCount: 450,
+      },
+      modified: '2021-04-29',
+      slug: '/the-post-slug',
+      title: 'et tempore sint',
+    };
+    const result = convertPostPreviewToArticlePreview(post);
+
+    expect(result.id).toBe(post.databaseId);
+    expect(result.intro).toBe(post.contentParts.beforeMore);
+    expect(result.meta.commentsCount).toBe(post.commentCount);
+    expect(result.meta.cover).toBeUndefined();
+    expect(result.meta.dates.publication).toBe(post.date);
+    expect(result.meta.dates.update).toBe(post.modified);
+    expect(result.meta.thematics).toBeUndefined();
+    expect(result.meta.wordsCount).toBe(post.info.wordsCount);
+    expect(result.slug).toBe(post.slug);
+    expect(result.title).toBe(post.title);
+  });
+  /* eslint-enable max-statements */
+
+  it('can return 0 as comment count if not defined', () => {
+    const post: WPPostPreview = {
+      acfPosts: null,
+      commentCount: null,
+      contentParts: {
+        beforeMore:
+          'Et quos fuga molestias. Voluptatum nobis mollitia eaque dolorem sunt. Dolores dignissimos consequuntur mollitia. Enim molestias quibusdam sequi. Dolore ut quo. Libero iure non vel reprehenderit.',
+      },
+      databaseId: 5,
+      date: '2021-04-28',
+      featuredImage: null,
+      info: {
+        wordsCount: 450,
+      },
+      modified: '2021-04-29',
+      slug: '/the-post-slug',
+      title: 'et tempore sint',
+    };
+    const result = convertPostPreviewToArticlePreview(post);
+
+    expect(result.meta.commentsCount).toBe(0);
+  });
+
+  it('can convert the cover', () => {
+    const post = {
+      acfPosts: null,
+      commentCount: null,
+      contentParts: {
+        beforeMore:
+          'Et quos fuga molestias. Voluptatum nobis mollitia eaque dolorem sunt. Dolores dignissimos consequuntur mollitia. Enim molestias quibusdam sequi. Dolore ut quo. Libero iure non vel reprehenderit.',
+      },
+      databaseId: 5,
+      date: '2021-04-28',
+      featuredImage: {
+        node: {
+          altText: 'molestiae praesentium animi',
+          mediaDetails: {
+            height: 480,
+            width: 640,
+          },
+          sourceUrl: 'https://picsum.photos/640/480',
+          title: 'ullam deserunt perspiciatis',
+        },
+      },
+      info: {
+        wordsCount: 450,
+      },
+      modified: '2021-04-29',
+      slug: '/the-post-slug',
+      title: 'et tempore sint',
+    } satisfies WPPostPreview;
+    const result = convertPostPreviewToArticlePreview(post);
+
+    expect(result.meta.cover).toStrictEqual(
+      convertWPImgToImg(post.featuredImage.node)
+    );
+  });
+
+  it('can convert the thematics', () => {
+    const thematics: WPThematicPreview[] = [
+      { databaseId: 2, slug: '/thematic1', title: 'aut quis vel' },
+      { databaseId: 8, slug: '/thematic2', title: 'vel sint autem' },
+    ];
+    const post: WPPostPreview = {
+      acfPosts: {
+        postsInThematic: thematics,
+      },
+      commentCount: 6,
+      contentParts: {
+        beforeMore:
+          'Et quos fuga molestias. Voluptatum nobis mollitia eaque dolorem sunt. Dolores dignissimos consequuntur mollitia. Enim molestias quibusdam sequi. Dolore ut quo. Libero iure non vel reprehenderit.',
+      },
+      databaseId: 5,
+      date: '2021-04-28',
+      featuredImage: null,
+      info: {
+        wordsCount: 450,
+      },
+      modified: '2021-04-29',
+      slug: '/the-post-slug',
+      title: 'et tempore sint',
+    };
+    const result = convertPostPreviewToArticlePreview(post);
+
+    expect(result.meta.thematics).toStrictEqual(
+      thematics.map(convertTaxonomyToPageLink)
+    );
+  });
+});
diff --git a/src/services/graphql/helpers/convert-post-preview-to-article-preview.ts b/src/services/graphql/helpers/convert-post-preview-to-article-preview.ts
new file mode 100644
index 0000000..78777eb
--- /dev/null
+++ b/src/services/graphql/helpers/convert-post-preview-to-article-preview.ts
@@ -0,0 +1,36 @@
+import type { ArticlePreview, WPPostPreview } from '../../../types';
+import { convertTaxonomyToPageLink } from './convert-taxonomy-to-page-link';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+export const convertPostPreviewToArticlePreview = ({
+  acfPosts,
+  commentCount,
+  contentParts,
+  databaseId,
+  date,
+  featuredImage,
+  info,
+  modified,
+  slug,
+  title,
+}: WPPostPreview): ArticlePreview => {
+  return {
+    id: databaseId,
+    intro: contentParts.beforeMore,
+    meta: {
+      commentsCount: typeof commentCount === 'number' ? commentCount : 0,
+      cover: featuredImage ? convertWPImgToImg(featuredImage.node) : undefined,
+      dates: {
+        publication: date,
+        update: modified,
+      },
+      thematics:
+        acfPosts && 'postsInThematic' in acfPosts
+          ? acfPosts.postsInThematic?.map(convertTaxonomyToPageLink)
+          : undefined,
+      wordsCount: info.wordsCount,
+    },
+    slug,
+    title,
+  };
+};
diff --git a/src/services/graphql/helpers/convert-post-to-article.test.ts b/src/services/graphql/helpers/convert-post-to-article.test.ts
new file mode 100644
index 0000000..0a1c359
--- /dev/null
+++ b/src/services/graphql/helpers/convert-post-to-article.test.ts
@@ -0,0 +1,125 @@
+import { describe, expect, it } from '@jest/globals';
+import type { WPPost } from '../../../types';
+import { convertPostToArticle } from './convert-post-to-article';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+describe('convert-post-to-article', () => {
+  /* eslint-disable max-statements */
+  it('converts a WPPost object to an Article object', async () => {
+    const post: WPPost = {
+      acfPosts: null,
+      author: { node: { name: 'Vince5' } },
+      commentCount: 10,
+      contentParts: {
+        afterMore:
+          'Eum est rerum neque placeat iure veniam enim consequatur assumenda. Quos eos placeat ea et vel sit ratione fugit. Modi qui sint iure beatae illo voluptas.',
+        beforeMore:
+          'Omnis ab qui dolorem praesentium voluptas asperiores officiis. Id nostrum minus quae ducimus tenetur eum a rem eum. Aut odio libero sit soluta ullam odit.',
+      },
+      databaseId: 8,
+      date: '2022-05-04',
+      featuredImage: null,
+      info: { wordsCount: 300 },
+      modified: '2022-06-01',
+      seo: {
+        metaDesc: 'Est non debitis quas harum quasi voluptatem qui.',
+        title: 'consequuntur molestiae amet',
+      },
+      slug: '/the-post-slug',
+      title: 'ea vero repellat',
+    };
+    const result = await convertPostToArticle(post);
+
+    // eslint-disable-next-line @typescript-eslint/no-magic-numbers
+    expect.assertions(15);
+
+    expect(result.content).toBe(post.contentParts.afterMore);
+    expect(result.id).toBe(post.databaseId);
+    expect(result.intro).toBe(post.contentParts.beforeMore);
+    expect(result.meta.author).toBe(post.author.node.name);
+    expect(result.meta.commentsCount).toBe(post.commentCount);
+    expect(result.meta.cover).toBeUndefined();
+    expect(result.meta.dates.publication).toBe(post.date);
+    expect(result.meta.dates.update).toBe(post.modified);
+    expect(result.meta.seo.description).toBe(post.seo.metaDesc);
+    expect(result.meta.seo.title).toBe(post.seo.title);
+    expect(result.meta.thematics).toBeUndefined();
+    expect(result.meta.topics).toBeUndefined();
+    expect(result.meta.wordsCount).toBe(post.info.wordsCount);
+    expect(result.slug).toBe(post.slug);
+    expect(result.title).toBe(post.title);
+  });
+  /* eslint-enable max-statements */
+
+  it('can convert the cover', async () => {
+    const post = {
+      acfPosts: null,
+      author: { node: { name: 'Vince5' } },
+      commentCount: null,
+      contentParts: {
+        afterMore:
+          'Eum est rerum neque placeat iure veniam enim consequatur assumenda. Quos eos placeat ea et vel sit ratione fugit. Modi qui sint iure beatae illo voluptas.',
+        beforeMore:
+          'Omnis ab qui dolorem praesentium voluptas asperiores officiis. Id nostrum minus quae ducimus tenetur eum a rem eum. Aut odio libero sit soluta ullam odit.',
+      },
+      databaseId: 8,
+      date: '2022-05-04',
+      featuredImage: {
+        node: {
+          altText: 'molestiae praesentium animi',
+          mediaDetails: {
+            height: 480,
+            width: 640,
+          },
+          sourceUrl: 'https://picsum.photos/640/480',
+          title: 'ullam deserunt perspiciatis',
+        },
+      },
+      info: { wordsCount: 300 },
+      modified: '2022-06-01',
+      seo: {
+        metaDesc: 'Est non debitis quas harum quasi voluptatem qui.',
+        title: 'consequuntur molestiae amet',
+      },
+      slug: '/the-post-slug',
+      title: 'ea vero repellat',
+    } satisfies WPPost;
+    const result = await convertPostToArticle(post);
+
+    expect.assertions(1);
+
+    expect(result.meta.cover).toStrictEqual(
+      convertWPImgToImg(post.featuredImage.node)
+    );
+  });
+
+  it('can return 0 as comment count when not defined', async () => {
+    const post: WPPost = {
+      acfPosts: null,
+      author: { node: { name: 'Vince5' } },
+      commentCount: null,
+      contentParts: {
+        afterMore:
+          'Eum est rerum neque placeat iure veniam enim consequatur assumenda. Quos eos placeat ea et vel sit ratione fugit. Modi qui sint iure beatae illo voluptas.',
+        beforeMore:
+          'Omnis ab qui dolorem praesentium voluptas asperiores officiis. Id nostrum minus quae ducimus tenetur eum a rem eum. Aut odio libero sit soluta ullam odit.',
+      },
+      databaseId: 8,
+      date: '2022-05-04',
+      featuredImage: null,
+      info: { wordsCount: 300 },
+      modified: '2022-06-01',
+      seo: {
+        metaDesc: 'Est non debitis quas harum quasi voluptatem qui.',
+        title: 'consequuntur molestiae amet',
+      },
+      slug: '/the-post-slug',
+      title: 'ea vero repellat',
+    };
+    const result = await convertPostToArticle(post);
+
+    expect.assertions(1);
+
+    expect(result.meta.commentsCount).toBe(0);
+  });
+});
diff --git a/src/services/graphql/helpers/convert-post-to-article.ts b/src/services/graphql/helpers/convert-post-to-article.ts
new file mode 100644
index 0000000..b540a77
--- /dev/null
+++ b/src/services/graphql/helpers/convert-post-to-article.ts
@@ -0,0 +1,43 @@
+import type { Article, WPPost } from '../../../types';
+import { updateContentTree } from '../../../utils/helpers';
+import { convertTaxonomyToPageLink } from './convert-taxonomy-to-page-link';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+export const convertPostToArticle = async ({
+  acfPosts,
+  author,
+  commentCount,
+  contentParts,
+  databaseId,
+  date,
+  featuredImage,
+  info,
+  modified,
+  seo,
+  slug,
+  title,
+}: WPPost): Promise<Article> => {
+  return {
+    content: await updateContentTree(contentParts.afterMore),
+    id: databaseId,
+    intro: contentParts.beforeMore,
+    meta: {
+      author: author.node.name,
+      commentsCount: commentCount ?? 0,
+      cover: featuredImage ? convertWPImgToImg(featuredImage.node) : undefined,
+      dates: {
+        publication: date,
+        update: modified,
+      },
+      seo: {
+        description: seo.metaDesc,
+        title: seo.title,
+      },
+      thematics: acfPosts?.postsInThematic?.map(convertTaxonomyToPageLink),
+      topics: acfPosts?.postsInTopic?.map(convertTaxonomyToPageLink),
+      wordsCount: info.wordsCount,
+    },
+    slug,
+    title,
+  };
+};
diff --git a/src/services/graphql/helpers/convert-recent-post-to-recent-article.test.ts b/src/services/graphql/helpers/convert-recent-post-to-recent-article.test.ts
new file mode 100644
index 0000000..8acf753
--- /dev/null
+++ b/src/services/graphql/helpers/convert-recent-post-to-recent-article.test.ts
@@ -0,0 +1,48 @@
+import { describe, expect, it } from '@jest/globals';
+import type { RecentWPPost } from '../../../types';
+import { convertRecentPostToRecentArticle } from './convert-recent-post-to-recent-article';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+describe('convert-recent-post-to-recent-article', () => {
+  it('converts a RecentWPPost object to a RecentArticle object', () => {
+    const post: RecentWPPost = {
+      databaseId: 5,
+      date: '2022-03-20',
+      featuredImage: null,
+      slug: '/the-post-slug',
+      title: 'veritatis ex autem',
+    };
+    const result = convertRecentPostToRecentArticle(post);
+
+    expect(result.cover).toBeUndefined();
+    expect(result.id).toBe(post.databaseId);
+    expect(result.publicationDate).toBe(post.date);
+    expect(result.slug).toBe(post.slug);
+    expect(result.title).toBe(post.title);
+  });
+
+  it('can convert the cover', () => {
+    const post = {
+      databaseId: 5,
+      date: '2022-03-20',
+      featuredImage: {
+        node: {
+          altText: 'molestiae praesentium animi',
+          mediaDetails: {
+            height: 480,
+            width: 640,
+          },
+          sourceUrl: 'https://picsum.photos/640/480',
+          title: 'ullam deserunt perspiciatis',
+        },
+      },
+      slug: '/the-post-slug',
+      title: 'veritatis ex autem',
+    } satisfies RecentWPPost;
+    const result = convertRecentPostToRecentArticle(post);
+
+    expect(result.cover).toStrictEqual(
+      convertWPImgToImg(post.featuredImage.node)
+    );
+  });
+});
diff --git a/src/services/graphql/helpers/convert-recent-post-to-recent-article.ts b/src/services/graphql/helpers/convert-recent-post-to-recent-article.ts
new file mode 100644
index 0000000..ff5eb67
--- /dev/null
+++ b/src/services/graphql/helpers/convert-recent-post-to-recent-article.ts
@@ -0,0 +1,24 @@
+import type { RecentArticle, RecentWPPost } from '../../../types';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+/**
+ * Convert a WordPress post to an article.
+ *
+ * @param {RecentWPPost} post - A post.
+ * @returns {RecentArticle} An article.
+ */
+export const convertRecentPostToRecentArticle = ({
+  databaseId,
+  date,
+  featuredImage,
+  slug,
+  title,
+}: RecentWPPost): RecentArticle => {
+  return {
+    cover: featuredImage ? convertWPImgToImg(featuredImage.node) : undefined,
+    id: databaseId,
+    publicationDate: date,
+    slug,
+    title,
+  };
+};
diff --git a/src/services/graphql/helpers/convert-taxonomy-to-page-link.test.ts b/src/services/graphql/helpers/convert-taxonomy-to-page-link.test.ts
new file mode 100644
index 0000000..b687ccb
--- /dev/null
+++ b/src/services/graphql/helpers/convert-taxonomy-to-page-link.test.ts
@@ -0,0 +1,52 @@
+import { describe, expect, it } from '@jest/globals';
+import type { WPThematicPreview, WPTopicPreview } from '../../../types';
+import { convertTaxonomyToPageLink } from './convert-taxonomy-to-page-link';
+
+describe('convert-taxonomy-to-page-link', () => {
+  it('can convert a WPThematicPreview object to a Thematic object', () => {
+    const thematic: WPThematicPreview = {
+      databaseId: 42,
+      slug: '/the-thematic-slug',
+      title: 'et ut alias',
+    };
+    const result = convertTaxonomyToPageLink(thematic);
+
+    expect(result.id).toBe(thematic.databaseId);
+    expect(result.logo).toBeUndefined();
+    expect(result.name).toBe(thematic.title);
+    expect(result.url).toBe(thematic.slug);
+  });
+
+  it('can convert a WPTopicPreview object to a Topic object', () => {
+    const topic: WPTopicPreview = {
+      databaseId: 42,
+      featuredImage: {
+        node: {
+          altText: 'dolorem quia possimus',
+          mediaDetails: {
+            height: 480,
+            width: 640,
+          },
+          sourceUrl: 'https://picsum.photos/640/480',
+          title: 'eos',
+        },
+      },
+      slug: '/the-topic-slug',
+      title: 'et ut alias',
+    };
+    const result = convertTaxonomyToPageLink(topic);
+
+    expect(result.id).toBe(topic.databaseId);
+    expect(result.logo?.alt).toBe(topic.featuredImage?.node.altText);
+    expect(result.logo?.height).toBe(
+      topic.featuredImage?.node.mediaDetails.height
+    );
+    expect(result.logo?.src).toBe(topic.featuredImage?.node.sourceUrl);
+    expect(result.logo?.title).toBe(topic.featuredImage?.node.title);
+    expect(result.logo?.width).toBe(
+      topic.featuredImage?.node.mediaDetails.width
+    );
+    expect(result.name).toBe(topic.title);
+    expect(result.url).toBe(topic.slug);
+  });
+});
diff --git a/src/services/graphql/helpers/convert-taxonomy-to-page-link.ts b/src/services/graphql/helpers/convert-taxonomy-to-page-link.ts
new file mode 100644
index 0000000..2294fb7
--- /dev/null
+++ b/src/services/graphql/helpers/convert-taxonomy-to-page-link.ts
@@ -0,0 +1,23 @@
+import type {
+  PageLink,
+  WPThematicPreview,
+  WPTopicPreview,
+} from '../../../types';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+export const convertTaxonomyToPageLink = ({
+  databaseId,
+  slug,
+  title,
+  ...props
+}: WPThematicPreview | WPTopicPreview): PageLink => {
+  return {
+    id: databaseId,
+    logo:
+      'featuredImage' in props && props.featuredImage
+        ? convertWPImgToImg(props.featuredImage.node)
+        : undefined,
+    name: title,
+    url: slug,
+  };
+};
diff --git a/src/services/graphql/helpers/convert-wp-comment-to-comment.test.ts b/src/services/graphql/helpers/convert-wp-comment-to-comment.test.ts
new file mode 100644
index 0000000..4b385b4
--- /dev/null
+++ b/src/services/graphql/helpers/convert-wp-comment-to-comment.test.ts
@@ -0,0 +1,93 @@
+import { describe, expect, it } from '@jest/globals';
+import type { WPComment } from '../../../types';
+import { convertWPCommentToComment } from './convert-wp-comment-to-comment';
+
+describe('convert-wp-comment-to-comment', () => {
+  it('converts a WPComment object to a Comment object', () => {
+    const comment: WPComment = {
+      approved: true,
+      author: {
+        node: {
+          avatar: null,
+          name: 'Maribel.Roberts',
+          url: null,
+        },
+      },
+      content: 'Aliquam qui et facere consequatur quia.',
+      databaseId: 4,
+      date: '2023-10-15',
+      parentDatabaseId: 1,
+      status: 'HOLD',
+    };
+
+    const transformedComment = convertWPCommentToComment(comment);
+
+    expect(transformedComment.content).toBe(comment.content);
+    expect(transformedComment.id).toBe(comment.databaseId);
+    expect(transformedComment.isApproved).toBe(comment.approved);
+    expect(transformedComment.meta.author.avatar).toBeUndefined();
+    expect(transformedComment.meta.author.name).toBe(comment.author.node.name);
+    expect(transformedComment.meta.author.website).toBeUndefined();
+    expect(transformedComment.parentId).toBe(comment.parentDatabaseId);
+    expect(transformedComment.replies).toStrictEqual([]);
+  });
+
+  it('can convert the avatar', () => {
+    const comment: WPComment = {
+      approved: true,
+      author: {
+        node: {
+          avatar: {
+            height: 80,
+            url: 'https://cloudflare-ipfs.com/ipfs/Qmd3W5DuhgHirLHGVixi6V76LhCkZUz6pnFt5AJBiyvHye/avatar/426.jpg',
+            width: 80,
+          },
+          name: 'Maribel.Roberts',
+          url: null,
+        },
+      },
+      content: 'Aliquam qui et facere consequatur quia.',
+      databaseId: 4,
+      date: '2023-10-15',
+      parentDatabaseId: 1,
+      status: 'HOLD',
+    };
+
+    const transformedComment = convertWPCommentToComment(comment);
+
+    expect(transformedComment.meta.author.avatar?.alt).toBe(
+      `${comment.author.node.name} avatar`
+    );
+    expect(transformedComment.meta.author.avatar?.height).toBe(
+      comment.author.node.avatar?.height
+    );
+    expect(transformedComment.meta.author.avatar?.src).toBe(
+      comment.author.node.avatar?.url
+    );
+    expect(transformedComment.meta.author.avatar?.width).toBe(
+      comment.author.node.avatar?.width
+    );
+  });
+
+  it('can remove the parentId when not meaningful', () => {
+    const comment: WPComment = {
+      approved: true,
+      author: {
+        node: {
+          avatar: null,
+          name: 'Maribel.Roberts',
+          url: null,
+        },
+      },
+      content: 'Aliquam qui et facere consequatur quia.',
+      databaseId: 4,
+      date: '2023-10-15',
+      parentDatabaseId: 0,
+      status: 'HOLD',
+    };
+
+    const transformedComment = convertWPCommentToComment(comment);
+
+    expect(transformedComment.parentId).toBeUndefined();
+  });
+});
diff --git a/src/services/graphql/helpers/convert-wp-comment-to-comment.ts b/src/services/graphql/helpers/convert-wp-comment-to-comment.ts
new file mode 100644
index 0000000..7a7e2ca
--- /dev/null
+++ b/src/services/graphql/helpers/convert-wp-comment-to-comment.ts
@@ -0,0 +1,35 @@
+import type { SingleComment, WPComment } from '../../../types';
+
+/**
+ * Convert a comment from WordPress type to SingleComment.
+ *
+ * @param {WPComment} comment - A raw comment from WordPress.
+ * @returns {SingleComment} A comment.
+ */
+export const convertWPCommentToComment = (
+  comment: WPComment
+): SingleComment => {
+  return {
+    content: comment.content,
+    isApproved: comment.approved,
+    id: comment.databaseId,
+    meta: {
+      author: {
+        name: comment.author.node.name,
+        avatar: comment.author.node.avatar
+          ? {
+              alt: `${comment.author.node.name} avatar`,
+              height: comment.author.node.avatar.height,
+              src: comment.author.node.avatar.url,
+              width: comment.author.node.avatar.width,
+            }
+          : undefined,
+        website: comment.author.node.url ?? undefined,
+      },
+      date: comment.date,
+    },
+    parentId:
+      comment.parentDatabaseId === 0 ? undefined : comment.parentDatabaseId,
+    replies: [],
+  };
+};
diff --git a/src/services/graphql/helpers/convert-wp-image-to-img.test.ts b/src/services/graphql/helpers/convert-wp-image-to-img.test.ts
new file mode 100644
index 0000000..ca58a4f
--- /dev/null
+++ b/src/services/graphql/helpers/convert-wp-image-to-img.test.ts
@@ -0,0 +1,41 @@
+import { describe, expect, it } from '@jest/globals';
+import type { WPImage } from '../../../types';
+import { convertWPImgToImg } from './convert-wp-image-to-img';
+
+describe('convert-wp-image-to-img', () => {
+  it('converts a WPImage object to an Img object', () => {
+    const img: WPImage = {
+      altText: 'molestiae praesentium animi',
+      mediaDetails: {
+        height: 480,
+        width: 640,
+      },
+      sourceUrl: 'https://picsum.photos/640/480',
+      title: null,
+    };
+
+    const transformedImg = convertWPImgToImg(img);
+
+    expect(transformedImg.alt).toBe(img.altText);
+    expect(transformedImg.height).toBe(img.mediaDetails.height);
+    expect(transformedImg.src).toBe(img.sourceUrl);
+    expect(transformedImg.title).toBeUndefined();
+    expect(transformedImg.width).toBe(img.mediaDetails.width);
+  });
+
+  it('can return an empty string if altText is missing', () => {
+    const img: WPImage = {
+      altText: null,
+      mediaDetails: {
+        height: 480,
+        width: 640,
+      },
+      sourceUrl: 'https://picsum.photos/640/480',
+      title: null,
+    };
+
+    const transformedImg = convertWPImgToImg(img);
+
+    expect(transformedImg.alt).toBe('');
+  });
+});
diff --git a/src/services/graphql/helpers/convert-wp-image-to-img.ts b/src/services/graphql/helpers/convert-wp-image-to-img.ts
new file mode 100644
index 0000000..392aaf9
--- /dev/null
+++ b/src/services/graphql/helpers/convert-wp-image-to-img.ts
@@ -0,0 +1,16 @@
+import type { Img, WPImage } from '../../../types';
+
+export const convertWPImgToImg = ({
+  altText,
+  mediaDetails,
+  sourceUrl,
+  title,
+}: WPImage): Img => {
+  return {
+    alt: altText ?? '',
+    height: mediaDetails.height,
+    src: sourceUrl,
+    title: title ?? undefined,
+    width: mediaDetails.width,
+  };
+};
diff --git a/src/services/graphql/helpers/index.ts b/src/services/graphql/helpers/index.ts
new file mode 100644
index 0000000..16e93d2
--- /dev/null
+++ b/src/services/graphql/helpers/index.ts
@@ -0,0 +1,7 @@
+export * from './build-comments-tree';
+export * from './convert-post-preview-to-article-preview';
+export * from './convert-post-to-article';
+export * from './convert-recent-post-to-recent-article';
+export * from './convert-taxonomy-to-page-link';
+export * from './convert-wp-comment-to-comment';
+export * from './convert-wp-image-to-img';