Javascript Function To Return Elasticsearch Results

I'm trying to write a JavaScript function that returns results of an Elasticsearch v5 query. I can't figure out where and how to include 'return' in this code. With the following,

Solution 1:

I would instanitate a new array outside of your client.search function in global scope and array.push your 'hits' Then access your newly filled array.

let newArr = [];
client.search(searchParams).then(function (resp) {
for(let i = 0; i < resp.hits.hits.length; i++){
newArr.push(resp.hits.hits[i]);
}
console.log('hits: ',newArr)
return newArr;
}, function (err) {
console.trace(err.message);
});

Solution 2:

First of all, elasticsearch js client is working with Promise ( I think using callback is also possible).

Using Promise is a good way to handle asynchronous computation.

In your question, you have already done something with a promise:

var search = function(id)
{
    var searchParams = { /** What your search is **/}
    return client.search(searchParams)
}

This call is returning a Promise. If we consider handleResponse as the function in your then

var handleResponse = function(resp)
{
    var hits = resp.hits.hits;
    console.log('hits: ',hits)
    return hits; //You could send back result here if using node 
}

In your code, handleResponse is called once the promise is fullfield. And in that code you are processing data. Don't forget you are in asynchronious, you need to keep working with promise to handle hits.

By the way, in your question, what you have done by using "then" is chaining Promise. It is normal to have Promise.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/then Promise.prototype.then is returning a Promise.

var segmentSearch = function ( id )
{
   return search
           .then( handleResponse //here you got your hit )
           .then( function ( hits ) 
           {
                console.log(hits) //and here you have done something with hits from search.
           })
}

Solution 3:

I neglected to post my fix, sorry about that. The sequence is to create searchParams, perform client.search(searchParams) which returns a Promise of hits, then process those hits:

segmentSearch = function(obj){
  // retrieve all segments associated with a place,
  // populate results <div>
  let html = ''
  var plKeys = Object.keys(obj)
  var relevantProjects = []

  for(let i = 0; i < plKeys.length; i++){
    relevantProjects.push(obj[plKeys[i]][0])

  var searchParams = {
    index: 'myIndex',
    type: 'segment',
    body: {
      query: {
        nested : {
            path : "properties",
            query : {
               match : {"properties.source" : id }
            },
            inner_hits : {}
        }
      }
    }
  }

  client.search(searchParams).then(function (resp) {
    return Promise.all(resp.hits.hits)
  }).then(function(hitsArray){
    ...write html to a <div> using hits results
  }
}