streams: Transform.by, rm unncessary check

David Mark Clements · David Mark Clements · commit 447a89581860 · 2019-12-16T12:00:24.000+01:00
diff --git a/lib/_stream_transform.js b/lib/_stream_transform.js
@@ -264,9 +264,6 @@ function SourceIterator(asyncGeneratorFn, opts) {
     this[kSourceIteratorResolve] = resolve;
   };
   const first = iter.next();
-  if (!first || typeof first.then !== 'function') {
-    throw new ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE('asyncGeneratorFn');
-  }
   this[kSourceIteratorPump](iter, first);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -264,9 +264,6 @@ function SourceIterator(asyncGeneratorFn, opts) {`
`264`	`264`	`this[kSourceIteratorResolve] = resolve;`
`265`	`265`	`};`
`266`	`266`	`const first = iter.next();`
`267`		`- if (!first \|\| typeof first.then !== 'function') {`
`268`		`- throw new ERR_ARG_RETURN_VALUE_NOT_ASYNC_ITERABLE('asyncGeneratorFn');`
`269`		`- }`
`270`	`267`	`this[kSourceIteratorPump](iter, first);`
`271`	`268`	`}`
`272`	`269`