feat: add filterFn argument to the injectContentFiles function (#348)

Closes #347

apps/docs-app/docs/features/routing/content.md

@@ -93,7 +93,7 @@ Hello World
 
 ## Using the Content Files List
 
-To get a list using the list of content files in the `src/content` folder, use the `injectContentFiles()` function from the `@analogjs/content` package in your component.
+To get a list using the list of content files in the `src/content` folder, use the `injectContentFiles<Attributes>(filterFn?: InjectContentFilesFilterFunction<Attributes>)` function from the `@analogjs/content` package in your component. To narrow the files, you can use the `filterFn` predicate function as an argument. You can use the `InjectContentFilesFilterFunction<T>` type to set up your predicate.
 
 ```ts
 import { Component } from '@angular/core';
@@ -122,7 +122,9 @@ export interface PostAttributes {
   `,
 })
 export default class BlogComponent {
-  readonly posts = injectContentFiles<PostAttributes>();
+  private readonly contentFilterFn: InjectContentFilesFilterFunction<PostAttributes> =
+    (contentFile) => !!contentFile.filename.includes('/src/content/blog/');
+  readonly posts = injectContentFiles<PostAttributes>(contentFilterFn);
 }
 ```
 

packages/content/src/lib/inject-content-files.spec.ts

@@ -2,7 +2,10 @@ import { TestBed } from '@angular/core/testing';
 import { expect } from 'vitest';
 import { CONTENT_FILES_LIST_TOKEN } from './content-files-list-token';
 import { ContentFile } from './content-file';
-import { injectContentFiles } from './inject-content-files';
+import {
+  injectContentFiles,
+  InjectContentFilesFilterFunction,
+} from './inject-content-files';
 
 describe('injectContentFiles', () => {
   it('should provide empty files if no files provided', () => {
@@ -27,16 +30,62 @@ describe('injectContentFiles', () => {
     const injectedFiles = injectContentFiles();
     expect(injectedFiles).toEqual(contentFiles);
   });
+  it('should filter the result based on the provided filter function', () => {
+    type TestAttributes = { testAttribute1: string; testAttribute2: number };
+    const contentFiles: ContentFile<TestAttributes>[] = [
+      {
+        filename: '/src/content/test.md',
+        slug: 'test',
+        attributes: {
+          testAttribute1: 'hello world',
+          testAttribute2: 2,
+        },
+        content: 'I am the content',
+      },
+      {
+        filename: '/src/content/projects/test.md',
+        slug: 'test-projects',
+        attributes: {
+          testAttribute1: 'hello world',
+          testAttribute2: 2,
+        },
+        content: 'I am the project',
+      },
+      {
+        filename: '/src/content/blog/test.md',
+        slug: 'test-blog',
+        attributes: {
+          testAttribute1: 'hello world',
+          testAttribute2: 2,
+        },
+        content: 'I am the blog post',
+      },
+    ];
+
+    const contentFilterFn: InjectContentFilesFilterFunction<TestAttributes> = (
+      contentFile
+    ) => !!contentFile.filename.includes('/src/content/blog/');
+    const { injectContentFiles } = setup<TestAttributes>(
+      contentFiles,
+      contentFilterFn
+    );
+    const injectedFiles = injectContentFiles();
+    const expectedContentFiles = [contentFiles[2]];
+    expect(injectedFiles).toEqual(expectedContentFiles);
+  });
 
   function setup<Attributes extends Record<string, any>>(
-    contentFiles: ContentFile[] = []
+    contentFiles: ContentFile[] = [],
+    filterFn?: InjectContentFilesFilterFunction<Attributes>
   ) {
     TestBed.overrideProvider(CONTENT_FILES_LIST_TOKEN, {
       useValue: contentFiles,
     });
     return {
       injectContentFiles: () =>
-        TestBed.runInInjectionContext(() => injectContentFiles<Attributes>()),
+        TestBed.runInInjectionContext(() =>
+          injectContentFiles<Attributes>(filterFn)
+        ),
     };
   }
 });

packages/content/src/lib/inject-content-files.ts

@@ -2,8 +2,23 @@ import { ContentFile } from './content-file';
 import { inject } from '@angular/core';
 import { CONTENT_FILES_LIST_TOKEN } from './content-files-list-token';
 
-export function injectContentFiles<
-  Attributes extends Record<string, any>
->(): ContentFile<Attributes>[] {
-  return inject(CONTENT_FILES_LIST_TOKEN) as ContentFile<Attributes>[];
+export function injectContentFiles<Attributes extends Record<string, any>>(
+  filterFn?: InjectContentFilesFilterFunction<Attributes>
+): ContentFile<Attributes>[] {
+  const allContentFiles = inject(
+    CONTENT_FILES_LIST_TOKEN
+  ) as ContentFile<Attributes>[];
+
+  if (filterFn) {
+    const filteredContentFiles = allContentFiles.filter(filterFn);
+
+    return filteredContentFiles;
+  }
+  return allContentFiles;
 }
+
+export type InjectContentFilesFilterFunction<T extends Record<string, any>> = (
+  value: ContentFile<T>,
+  index: number,
+  array: ContentFile<T>[]
+) => boolean;