Json parser error do to multiple write access

I have a node.js webserver and this webserver is call from around 50 different clients and at every call the same json file is opened and data is written into to the file.

I have code a check which looks like following:

let newtext= JSON.stringify(text);
if(JSON.parse(newtext))
{
 write new data into json
}

normaly this should be a check to help against errors in the Json file, but because this webserver is call from many clients at same time and all are using the same json file because of that i think a error come into the json file.

so my problem is that a error message come from node.js at another place where i read the json file with JSON.parse