If you have some text in another file , you could
fetch() the file and then assign its content to the
<meta name="description" content="Old description">
/* text file in the same directory with the new title */
.then(response => response.text())
.then(text => document.title = text)
/* This text could also be fetched from a file */
document.querySelector('meta[name="description"]').content = 'New description';
You could also have all the new data formatted as JSON and saved in a file. You would then use
response.json() instead of
response.text() to directly parse it into an object.
Does that help you?
Have a nice day,