[jira] [Created] (TINKERPOP-2167) Gremlin Javascript Traversal as async iterable

["Joe Strouth (JIRA)" <ji...@apache.org>]

Joe Strouth created TINKERPOP-2167:
--------------------------------------

             Summary: Gremlin Javascript Traversal as async iterable
                 Key: TINKERPOP-2167
                 URL: https://issues.apache.org/jira/browse/TINKERPOP-2167
             Project: TinkerPop
          Issue Type: Improvement
          Components: javascript
    Affects Versions: 3.4.0
         Environment: Node v10.15.0
            Reporter: Joe Strouth


Traversals in Gremlin javascript are async iterators, as they implement a {{next()}} method that returns a Promise, which resolves to an object with {{value}} and {{done}} properties. It would be helpful if they were also async iterables - traversable via {{for await ... of}} loops.
{code:javascript}
(async function() {
  for await (const continent of g.V().hasLabel('continent').values('desc')) {
    console.log(continent)
  }
})()
{code}
Expected output:
{noformat}
> Africa
Antarctica
North America
Asia
Oceania
Europe
South America
{noformat}
Current output: (Node v10.15.0)
{noformat}
> (node:14698) UnhandledPromiseRejectionWarning: TypeError: g.V(...).hasLabel(...).values(...) is not a function or its return value is not async iterable
    at repl:1:78
    at repl:1:122
    at Script.runInThisContext (vm.js:96:20)
    at REPLServer.defaultEval (repl.js:332:29)
    at bound (domain.js:395:14)
    at REPLServer.runBound [as eval] (domain.js:408:12)
    at REPLServer.onLine (repl.js:639:10)
    at REPLServer.emit (events.js:187:15)
    at REPLServer.EventEmitter.emit (domain.js:441:20)
    at REPLServer.Interface._onLine (readline.js:290:10)
(node:14698) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:14698) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
{noformat}
This can be achieved by adding a {{[Symbol.asyncIterator]}} method to the Traversal class.



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