fix: Improve warning & avoid TypeError on bad YAML 1.1 nodes (fixes #610)

Author: eemeli

src/compose/compose-collection.ts

@@ -108,11 +108,11 @@ export function composeCollection(
       ctx.schema.tags.push(Object.assign({}, kt, { default: false }))
       tag = kt
     } else {
-      if (kt?.collection) {
+      if (kt) {
         onError(
           tagToken,
           'BAD_COLLECTION_TYPE',
-          `${kt.tag} used for ${expType} collection, but expects ${kt.collection}`,
+          `${kt.tag} used for ${expType} collection, but expects ${kt.collection ?? 'scalar'}`,
           true
         )
       } else {

src/schema/yaml-1.1/binary.ts

@@ -34,6 +34,7 @@ export const binary: ScalarTag = {
   },
 
   stringify({ comment, type, value }, ctx, onComment, onChompKeep) {
+    if (!value) return ''
     const buf = value as Uint8Array // checked earlier by binary.identify()
     let str: string
     if (typeof Buffer === 'function') {

src/schema/yaml-1.1/timestamp.ts

@@ -116,5 +116,5 @@ export const timestamp: ScalarTag & { test: RegExp } = {
   },
 
   stringify: ({ value }) =>
-    (value as Date).toISOString().replace(/(T00:00:00)?\.000Z$/, '')
+    (value as Date)?.toISOString().replace(/(T00:00:00)?\.000Z$/, '') ?? ''
 }

tests/doc/parse.ts

@@ -624,6 +624,24 @@ describe('handling complex keys', () => {
     expect(obj).toMatchObject([{ '[ foo ]': 'bar' }])
     expect(process.emitWarning).toHaveBeenCalled()
   })
+
+  test('Error on unresolved !!binary node with mapAsMap: false (#610)', () => {
+    process.emitWarning = jest.fn()
+    const doc = YAML.parseDocument('? ? !!binary ? !!binary')
+    expect(doc.warnings).toMatchObject([{ code: 'BAD_COLLECTION_TYPE' }])
+    doc.toJS()
+    expect(process.emitWarning).toHaveBeenCalled()
+  })
+
+  test('Error on unresolved !!timestamp node with mapAsMap: false (#610)', () => {
+    process.emitWarning = jest.fn()
+    const doc = YAML.parseDocument(
+      '? ? !!timestamp ? !!timestamp 2025-03-15T15:35:58.586Z'
+    )
+    expect(doc.warnings).toMatchObject([{ code: 'BAD_COLLECTION_TYPE' }])
+    doc.toJS()
+    expect(process.emitWarning).toHaveBeenCalled()
+  })
 })
 
 test('Document.toJS({ onAnchor })', () => {