fix(safe-stringify): stringify falsy values and strings (#37)

* fix(safe-stringify): stringify falsy values and strings

* revert: do not stringify string twice

src/__tests__/safeStringify.spec.ts

@@ -4,9 +4,16 @@ describe('safeStringify', () => {
   it('should work', () => {
     const val = { foo: true };
 
-    expect(safeStringify(val)).toEqual(`foo: true
-`);
+    expect(safeStringify(val)).toEqual('foo: true\n');
+  });
+
+  it('should not stringify strings twice', () => {
     expect(safeStringify('foo: true')).toEqual('foo: true');
+    expect(safeStringify('')).toEqual('');
+  });
+
+  it.each([0, null, false])('should stringify falsy value: %s', value => {
+    expect(safeStringify(value)).toEqual(`${value}\n`);
   });
 
   it('should respect lineWidth for multi-line strings', () => {

src/safeStringify.ts

@@ -1,7 +1,4 @@
 import { DumpOptions, safeDump } from '@stoplight/yaml-ast-parser';
 
-export const safeStringify = (value: any, options?: DumpOptions): string => {
-  if (!value || typeof value === 'string') return value;
-
-  return safeDump(value, options);
-};
+export const safeStringify = (value: unknown, options?: DumpOptions): string =>
+  typeof value === 'string' ? value : safeDump(value, options);