feat(frontmatter): implement getFrontmatterBlock method (#23)

stoplightio · Mar 4, 2020 · e4aee86 · e4aee86
1 parent b0785b6
commit e4aee86
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diff --git a/src/consts.ts b/src/consts.ts
diff --git a/src/frontmatter/__tests__/fronmatter.spec.ts b/src/frontmatter/__tests__/fronmatter.spec.ts
@@ -2,6 +2,7 @@ import * as fs from 'fs';
 import { join } from 'path';
 import * as Unist from 'unist';
 
+import { parse } from '../../parse';
 import { parseWithPointers } from '../../parseWithPointers';
 import { stringify } from '../../stringify';
 import { Frontmatter } from '../frontmatter';
@@ -38,6 +39,10 @@ describe('Frontmatter', () => {
       expect(instance.get('test')).toBeUndefined();
     });
 
+    it('getFrontmatterBlock should return undefined', () => {
+      expect(Frontmatter.getFrontmatterBlock(fixture)).toBeUndefined();
+    });
+
     describe('set', () => {
       it('should create frontmatter block', () => {
         const instance = new Frontmatter(fixture);
@@ -67,6 +72,13 @@ foo: 123
       expect(instance.getAll()).toEqual({});
     });
 
+    it('getFrontmatterBlock should return block', () => {
+      expect(Frontmatter.getFrontmatterBlock(invalid)).toEqual(`---
+tti
+tags: [Hubs]
+---`);
+    });
+
     describe('set', () => {
       it('should update frontmatter block correctly', () => {
         const instance = new Frontmatter(invalid);
@@ -108,6 +120,13 @@ tags: [test]
       });
     });
 
+    it('getFrontmatterBlock should return block', () => {
+      expect(Frontmatter.getFrontmatterBlock(tags)).toEqual(`---
+title: Graphite Introduction
+tags: ['introductions', 'guides']
+---`);
+    });
+
     describe('#get', () => {
       it('should return value for single item', () => {
         const instance = new Frontmatter(tags);
@@ -285,4 +304,28 @@ Coolio.
       expect(instance.stringify()).toEqual(tags);
     });
   });
+
+  describe('getFrontmatterBlock method', () => {
+    it.each(['---', '------', '---\nfoo', '--\n---', '---\na--', '\na\n---'])(
+      'should return undefined for incomplete block `%s`',
+      document => {
+        const block = Frontmatter.getFrontmatterBlock(document);
+        expect(block).toBeUndefined();
+        expect(parse(document)).toEqual(
+          expect.objectContaining({
+            type: 'root',
+            children: expect.arrayContaining([expect.not.objectContaining({ type: 'yaml' })]),
+          }),
+        );
+      },
+    );
+
+    it.each(['---\n---', '---\nfoo\n---'])('should produce the same result for `%s`', () => {
+      const document = `---\n---`;
+      const block = Frontmatter.getFrontmatterBlock(document)!;
+
+      expect(block).toEqual(document);
+      expect(stringify(parse(block))).toEqual(stringify(parse(document)));
+    });
+  });
 });
diff --git a/src/frontmatter/frontmatter.ts b/src/frontmatter/frontmatter.ts
@@ -1,3 +1,4 @@
+import { Optional } from '@stoplight/types';
 import * as yaml from 'js-yaml';
 import { get, pullAt, set, toPath, unset } from 'lodash';
 import * as Unist from 'unist';
@@ -94,6 +95,12 @@ export class Frontmatter<T extends object = any> implements IFrontmatter<T> {
     return stringify(this.document);
   }
 
+  // based on https://github.com/remarkjs/remark-frontmatter/blob/3c18752b01af683d94641e47bd79581690a995b7/lib/parse.js
+  public static getFrontmatterBlock(value: string): Optional<string> {
+    const match = value.match(/^(\s*\n)?---.*?\n---/s);
+    return match === null ? void 0 : match[0];
+  }
+
   private updateDocument() {
     const children = this.document.children as Unist.Parent['children'] | undefined;
     if (!children) return;