fix: Serialize -0 as -0 (fixes #638)

Author: eemeli

src/stringify/stringifyNumber.ts

@@ -9,7 +9,7 @@ export function stringifyNumber({
   if (typeof value === 'bigint') return String(value)
   const num = typeof value === 'number' ? value : Number(value)
   if (!isFinite(num)) return isNaN(num) ? '.nan' : num < 0 ? '-.inf' : '.inf'
-  let n = JSON.stringify(value)
+  let n = Object.is(value, -0) ? '-0' : JSON.stringify(value)
   if (
     !format &&
     minFractionDigits &&

tests/doc/stringify.ts

@@ -43,6 +43,9 @@ for (const [name, version] of [
       test('Number', () => {
         expect(YAML.stringify(new Number(3.141), { version })).toBe('3.141\n')
       })
+      test('negative zero', () => {
+        expect(YAML.stringify(-0, { version })).toBe('-0\n')
+      })
 
       test('float with trailing zeros', () => {
         const doc = new YAML.Document<YAML.Scalar, false>(3, { version })