How to use the pelias-model.codec function in pelias-model

const geojsonify = require('../../../helper/geojsonify');
const proxyquire = require('proxyquire').noCallThru();
const codec = require('pelias-model').codec;

module.exports.tests = {};

module.exports.tests.interface = function(test, common) {
  test('valid interface', function(t) {
    t.equal(typeof geojsonify, 'function', 'geojsonify is a function');
    t.equal(geojsonify.length, 2, 'accepts x arguments');
    t.end();
  });
};

// ensure null island coordinates work
// ref: https://github.com/pelias/pelias/issues/84
module.exports.tests.earth = function(test, common) {
  test('earth', function(t) {
    var earth = [{

const GeoJSON = require('geojson');
const extent = require('@mapbox/geojson-extent');
const logger = require('pelias-logger').get('geojsonify');
const collectDetails = require('./geojsonify_place_details');
const _ = require('lodash');
const Document = require('pelias-model').Document;
const codec = require('pelias-model').codec;
const field = require('./fieldValue');
const decode_gid = require('./decode_gid');

function geojsonifyPlaces( params, docs ){

  // flatten & expand data for geojson conversion
  const geodata = docs
    .filter(doc => {
      if (!_.has(doc, 'center_point')) {
        logger.warn('No doc or center_point property');
        return false;
      } else {
        return true;
      }
    })
    .map(geojsonifyPlace.bind(null, params));