$filter returns undefined in async mode

[dprentis]

I am not able to use the filter function in async mode. It always returns undefined ie.

const out = await new Promise((resolve) => {
  const expression = jsonata('$filter(data, function($d) { true })');
  expression.evaluate(input, {}, (err, value) => {
    console.log('ERROR?', err); // null
    resolve(value); // undefined
  });
});

data is a valid array and the expression data returns the array. Also using $filter in synchronous mode works as expected (using version 1.5.3).

[andrew-coleman]

This is one example of a number of problems with the async mode of operation. I have now written an async test driver to run the whole test suite in async mode and fixed up all the failing cases, including this one.

[dprentis]

That's amazing - thanks!