A Node.js function to fetch weather station data then filter and shape it with JMESPath.

GetStationWeatherDataWithJmesPathQuery.js

let documentClient = require('documentdb').DocumentClient;
let jmespath = require('jmespath');
let cosmos_uri = process.env["STATION_COSMOS_URI"];
let cosmos_key = process.env["STATION_COSMOS_READONLY_KEY"];
let databaseId = process.env["STATION_COSMOS_DATABASE_NAME"];
let collectionId = process.env["STATION_COSMOS_COLLECTION_NAME"];
let client = new documentClient(cosmos_uri, { 'masterKey': cosmos_key });
let collectionLink = "/dbs/" + databaseId + "/colls/" + collectionId + "/";

module.exports = function (context, req) {
  let filterQuery = `SELECT * FROM c WHERE c.State = "${req.params.state}"`;
  try {
    let queryIterator = client.queryDocuments(collectionLink, filterQuery);
    queryIterator.toArray(function (err, matchingDocuments) {
      if (err) {
        context.done(err);
        return;
      }
      if (req.query && req.query.query) {
        try {
          matchingDocuments = jmespath.search(matchingDocuments, req.query.query);
        }
        catch (ex) {
          context.done(ex);
          return;
        }
      }
      context.done(null, { status: 200, body: matchingDocuments, headers: { 'Content-Type': 'application/json' }});
    });
  } catch (ex) {
    context.done(ex);
  }
};