How to keep your setting even after restart/reset

Have the use case to save app settings to be restore after startup/reset and decided to use .boot0.

This is the snippet I started with:

var defaults = { a:1, b:2, c:3 };
var s = require('Storage');
if (s.read('.boot0') === undefined) {
       s.write('.boot0',`var settings = ${JSON.stringify(defaults)}`);
       settings = defaults;
  }

print(settings);

// add  function to update `.boot0` if settings change ....

How do you save your app settings?