How to define global variable in Google Apps Script

Question

I see most examples from Google is they use only functions in a single giant script.

e.g. https://developers.google.com/apps-script/quickstart/macros

But in

Answer 1

You might be better off using the Properties Service as you can use these as a kind of persistent global variable.

click 'file > project properties > project properties' to set a key value, or you can use

PropertiesService.getScriptProperties().setProperty('mykey', 'myvalue');

The data can be retrieved with

var myvalue = PropertiesService.getScriptProperties().getProperty('mykey');