Create a workflow 5 equivalent of 'Dynamic External'

Provide an activity to run custom code outside of workflow then return back to workflow after certain user interaction. The arguments can be like:

in:

functionName: string

inputs:any

out

result:any

the 'functionName' argument will be used to find the javascript function in global scope. For example, when functionName = 'test', activity should call below function and finish itself (workflow runs next activity) when 'resolved':

function test(inputs){

 return new Promise(function(resolve) {

// some logic ...

let result = 'hello'

  resolve(result )

});

}