fix trimStart is undefined bug (#208)

markdoc · Sep 21, 2022 · 593a654 · 593a654
1 parent a18ffcc
commit 593a654
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Showing 2 changed files with 20 additions and 2 deletions.
diff --git a/src/formatter.test.ts b/src/formatter.test.ts
@@ -88,11 +88,27 @@ describe('Formatter', () => {
     expect(format(null)).toBe('');
   });
 
+  it('empty', () => {
+    check('', '');
+    stable('');
+  });
+
   it('basics', () => {
     check(source, expected);
     stable(expected);
   });
 
+  it('frontmatter', () => {
+    const source = `---
+title: Title
+subtitle: Subtitle
+---
+
+`;
+    check(source, source);
+    stable(source);
+  });
+
   it('attribute edge cases', () => {
     const source = `{% key id=$user.name class=default($y, "test") %}Child{% /key %}`;
     const expected = `

diff --git a/src/formatter.ts b/src/formatter.ts
@@ -92,10 +92,12 @@ function* formatFunction(f: Function) {
   yield ')';
 }
 
-function* trimStart(g: Generator) {
+function* trimStart(g: Generator<string>) {
   let n;
   do {
-    n = g.next().value.trimStart();
+    const { value, done } = g.next();
+    if (done) return;
+    n = value.trimStart();
   } while (!n.length);
   yield n;
   yield* g;