How to I save text from a document into a variable? - google-apps-script

Question

I want to take the text for a document and save it as a variable. I looked in the documentation and found "getText" something I think shall work. https://developers.google.com/apps-script/reference/document/footnote-section#gettext
I just get a problem when I try using it, because it's not a pre built function it gives the error massage "TypeError: Cannot read property 'getText' of null". So I looked at some more into it and noticed I needed Authorization:
"Scripts that use this method require authorization with one or more of the following scopes:
https://www.googleapis.com/auth/documents.currentonly
https://www.googleapis.com/auth/documents"
So how do I get the required authorization, do I need to do something different or is there another way i could do it?
It's just going to run on some of my docs for fun to se what funny things I am able to do with the program.
(New to programing, now the basics but just trying to see if programing is something for me)
Thanks in advance

Answer 1

Given with this sample document
You can start with this sample code below.
Code:
function myFunction() {
var body = DocumentApp.getActiveDocument().getBody();
var text = body.editAsText();
Logger.log(text.getText()); // returns all text in document ("Hey, search for me!!! I am <here>!!")
// 1. Regular expression (exec)
var regExp = new RegExp("<\(.*\)>", "gi"); // "i" is for case insensitive
var search = regExp.exec(text.getText())[1];
Logger.log(search); // returns "here"
// 2. (search)
Logger.log(text.getText().search(/here/)); // returns the index where the string was found, or -1 if not found
}
Output:
Note:
getText will return the text of the Class Text.
If you want to get a specific pattern from the document, you need to use Regular expression. I prefer the exec method. See usage for more details
For the authorization, you only need to click allow. I assume you are using apps script due to the tag.