DecSoft Support - Issue with writing and reading JSON files

Issue with writing and reading JSON files

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Bryce Beattie

I'm trying to use HTML compiler to save and load .json flavored text files. If I use javascript's JSON.stringify and JSON.parse I can encode and decode data fine. However, when I use stringify to get a string and write it to a file, then read it in to a string and use parse, Javascript throws an "unknown character" error.

For what it is worth, I opened the file written by appReadFile and copy and pasted the stringify results into a json validator, and it says the text is valid json.

If I have javascript write out those two strings (the one i write to the file and the one i read from the file, they strings look the same, but javascript says they are not === or ==.

Is it possible that appReadFile is inserting a hidden character somewhere?

DecSoft

Hello Bryce,

Certainly write and read operations don't add nothing to the file to be write or read. Look at the below "index.html" sample, I try it and works as expected after apply the "trim" function, so, probably you need to apply that "trim" function too?

<!DOCTYPE html>
<html lang="en" dir="ltr">
 <head>   
  <meta charset="utf-8">
  <meta name="viewport" 
   content="width=device-width, initial-scale=1">
  <title>HTML Compiler WriteFile Sample</title>
 </head>
 <body>

  <script>
   var
     writeJSON = function() {
       var
         person = {"name": "John", "lastname": "Doe"};
         
       external.appWriteFile('sample.json', JSON.stringify(person));
     };
     
   var
     trim = function (str) {
       return str.replace(/^\s+|\s+$/gm,'');
     };     
     
   var
     readJSON = function() {
       var
         person = JSON.parse(trim(external.appReadFile('sample.json')));
         
       alert(person.name + ' ' + person.lastname);   
     };     

  </script>

  <br>

  <button onclick="javascript:writeJSON();">Write JSON</button>
  
  <br>

  <button onclick="javascript:readJSON();">Read JSON</button>
  
 </body>
</html>

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Bryce Beattie

That did it. I'm not sure why JSON.parse can't deal with an extra whitespace character, but it's now working. Thanks!

DecSoft

Hello Bryce,

You're welcome! Certainly, I remember the "space" issue in other environments, languages, etc... I am not completely sure where, but, when you post here the issue, what I first before anything else is to trim the JSON... just because remember that I get the same issue in the past, not related with HTML Compiler!

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