code: function constraintsCall(constraints, connectType) {
      let emitterCall = new EventEmitter();
      // if docs found in couchDB database
      constraintsToQuery(constraints).on('docsFound', (docsResults) => {
          logger_1.logger.log('info', `Found ${docsResults.docs.length} docs for those constraints from ${connectType} request`);
          logger_1.logger.log('debug', `Doc list found \n ${JSON.stringify(docsResults)}`);
          logger_1.logger.log('debug', `constraints: ${JSON.stringify(constraints)}`);
          emitterCall.emit(`${connectType}Succeed`, docsResults.docs);
      })
          // if docs not found in couchDB database
          .on('noDocsFound', (docsResults) => {
          logger_1.logger.log('info', `No docs founds for constraints`);
          logger_1.logger.log('debug', `constraints: \n ${JSON.stringify(constraints)}`);
          emitterCall.emit(`${connectType}NoResults`, docsResults.docs);
      })
          // if an error occured
          .on('errorOnConstraints', (err) => {
          logger_1.logger.log('warn', `Constraints are empty or not in the right format`);
          emitterCall.emit(`${connectType}Failed`, err);
      });
      return emitterCall;
  }
docs: /*
  function that manage the call to the constraintsToQuery function. This part is listening on three event
  returned by the constraintsToQuery event: "docsFound", "noDocsFound" and "errorOnConstraints"
  @constraints : constraints to check
  @connectType : specify wich connection type