When parsing an array of objects, it fails if one object is null

[captixn]

Hi,

When parsing an array of object with:
var xls = json2xls(json)
I stumbled onto this error :

        if (n in object) {
              ^

TypeError: Cannot use 'in' operator to search for 'count' in null
    at getByString (C:\Users\capti\dev\essec_scraper\node_modules\�[4mjson2xls�[24m\lib\json2xls.js:33:15)
    at C:\Users\capti\dev\essec_scraper\node_modules\�[4mjson2xls�[24m\lib\json2xls.js:70:25
    at Array.map (<anonymous>)
    at C:\Users\capti\dev\essec_scraper\node_modules\�[4mjson2xls�[24m\lib\json2xls.js:69:23
    at Array.map (<anonymous>)
    at Function.transform.prepareJson (C:\Users\capti\dev\essec_scraper\node_modules\�[4mjson2xls�[24m\lib\json2xls.js:68:24)
    at transform (C:\Users\capti\dev\essec_scraper\node_modules\�[4mjson2xls�[24m\lib\json2xls.js:4:26)
    at file:///C:/Users/capti/dev/essec_scraper/convertData.js:7:11
�[90m    at ModuleJob.run (internal/modules/esm/module_job.js:152:23)�[39m
�[90m    at async Loader.import (internal/modules/esm/loader.js:166:24)�[39m

It appears function getByString(object, path) does not check for null for "object".
Therefore,

transform.prepareJson = function(json,config) {
....
res.rows = jsonArr.map(function(row) {
        return fields.map(function(key) {
            var value = getByString(row,key);

Will fail.
As a simple fix, I added

    if(object == null){
        return ""
    } 

to function getByString(object, path).
So that the rest of the array can be prepared..