Fix

Author: qwtel

json-parse-stream.ts

@@ -77,10 +77,9 @@ export class JSONParseNexus<T = any> extends TransformStream<string | Uint8Array
   }
 
   promise<T = any>(jsonPath: string): JSONParseLazyPromise<T | undefined> {
-    const stream = this.stream(jsonPath);
+    const reader = this.stream(jsonPath).getReader();
     return JSONParseLazyPromise.from(async () => {
-      if (!this.writable.locked) throw TypeError('Cannot await result while there\'s no data source.')
-      const x = await stream.getReader().read();
+      const x = await reader.read();
       return x.done ? undefined : x.value;
     })
   }
@@ -92,7 +91,6 @@ export class JSONParseNexus<T = any> extends TransformStream<string | Uint8Array
         this.#queues.set(path, queue)
       },
       pull: async () => {
-        if (!this.writable.locked) throw TypeError('Cannot await result while there\'s no data source.')
         while (true) {
           const { done, value } = await this.#reader.read();
           // FIXME: avoid duplicate match

test/json-parse-stream.test.ts

@@ -288,3 +288,19 @@ test('iterations throws without data source', () => {
   const items = nexus.iterable('$.items.*')
   assertRejects(() => items.next(), TypeError)
 })
+
+test('stream remains open when only promises left', async () => {
+  const nexus = new JSONParseNexus();
+
+  const stream = nexus.stream('$.items.*')
+  const type = nexus.promise('$.type')
+
+  new JSONStringifyReadable({ 
+    items: asyncGen(items), 
+    type: 'foo',
+  }).pipeThrough(nexus)
+
+  await collect(stream)
+  await timeout(10)
+  assertEquals(await type, 'foo')
+})