refactor: move frontmatter parser into commons package

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

commons/src/note-frontmatter-parser/parse-raw-frontmatter-from-yaml.spec.ts

@@ -0,0 +1,76 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { parseRawFrontmatterFromYaml } from './parse-raw-frontmatter-from-yaml.js'
+import { describe, expect, it } from '@jest/globals'
+
+describe('yaml frontmatter', () => {
+  it('should parse "title"', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml('title: test')
+    expect(noteFrontmatter.value?.title).toEqual('test')
+  })
+
+  it('should parse "robots"', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml('robots: index, follow')
+    expect(noteFrontmatter.value?.robots).toEqual('index, follow')
+  })
+
+  it('should parse the deprecated tags syntax', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml('tags: test123, abc')
+    expect(noteFrontmatter.value?.tags).toEqual('test123, abc')
+  })
+
+  it('should parse the tags list syntax', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml(`tags:
+      - test123
+      - abc
+    `)
+    expect(noteFrontmatter.value?.tags).toEqual(['test123', 'abc'])
+  })
+
+  it('should parse the tag inline-list syntax', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml(
+      "tags: ['test123', 'abc']"
+    )
+    expect(noteFrontmatter.value?.tags).toEqual(['test123', 'abc'])
+  })
+
+  it('should parse "breaks"', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml('breaks: false')
+    expect(noteFrontmatter.value?.breaks).toEqual(false)
+  })
+
+  it('should parse an opengraph title', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml(`opengraph:
+      title: Testtitle
+    `)
+    expect(noteFrontmatter.value?.opengraph.title).toEqual('Testtitle')
+  })
+
+  it('should parse multiple opengraph values', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml(`opengraph:
+      title: Testtitle
+      image: https://dummyimage.com/48.png
+      image:type: image/png
+    `)
+    expect(noteFrontmatter.value?.opengraph.title).toEqual('Testtitle')
+    expect(noteFrontmatter.value?.opengraph.image).toEqual(
+      'https://dummyimage.com/48.png'
+    )
+    expect(noteFrontmatter.value?.opengraph['image:type']).toEqual('image/png')
+  })
+
+  it('allows unknown additional options', () => {
+    const noteFrontmatter = parseRawFrontmatterFromYaml(`title: title
+additonal: "additonal"`)
+
+    expect(noteFrontmatter.value?.title).toBe('title')
+  })
+
+  it('throws an error if the yaml is invalid', () => {
+    const a = parseRawFrontmatterFromYaml('A: asd\n  B: asd')
+    expect(a.error?.message).toStrictEqual('Invalid YAML')
+  })
+})