Remove all but the text written by user - node.js

Question

I use Outlook API to fetch the sent email's body. Now, I want to clean the body to remove all links, headers, etc. and keep only the text written by user. Following is my regex function:
function getRegex() {
var regex1 = /^(?=.*Forwarded message)[^]*/m;
var regex2 = /^(?=.*From: )[^]*/m;
var regex3 = /^(?=.*On )[^]*/m;
var regex4 = /^(?=.*http)[^]*/m;
return new RegExp("(" + regex1.source + ")|(" + regex2.source + ")|(" + regex3.source + ")|(" + regex4.source + ")");
}
Following is function to fetch sent emails from Outlook:
outlook.mail.getMessages({
token: token.token.access_token,
odataParams: queryParams,
folderId: 'SentItems'
}, function (err, result) {
if (err){
console.log(err);
return;
}
var mail_array = result.value;
var outlook_sent_emails = '';
mail_array.forEach(function (mail) {
if (mail.BodyPreview !== '') {
outlook_sent_emails += (mail.BodyPreview + " ");
}
});
console.log(outlook_sent_emails.replace(getRegex(), "")); //This is not working
});
This line console.log(outlook_sent_emails.replace(getRegex(), "")); shows I am still getting all links, headers, etc.
The same regex is working elsewhere in my code.
EDITED:
Sample Text:
From: <Name>
Sent: <Datetime>
To: <Name>
Subj Dear Sir/Madam
Hi Vaibhav,
Hope you are doing well.
http://developer.android.com/sdk/index.html
Sent from my Windows 10 phone
I want to remove all kinds of links and text like as follows from the string:
From: <Name>
Sent: <Datetime>
To: <Name>
Subj Dear Sir/Madam
EXPECTED OUTPUT:
Hi Vaibhav,
Hope you are doing well.

Answer 1

UPDATE: added http
You may try this:
^.*(From:|Sent:|Sent\s+From|To:|Subj|Dear\s+(Sir|Madam)|http).*$
and replace by ""
Demo
const regex = /^.*(From:|Sent:|Sent\s+From|To:|Subj|Dear\s+(Sir|Madam)|http).*$/gmi;
const str = ` From: <Name>
Sent: <Datetime>
To: <Name>
Subj Dear Sir/Madam
Hi Vaibhav,
Hope you are doing well.
http://developer.android.com/sdk/index.html
Sent from my Windows 10 phone`;
const subst = ``;
const result = str.replace(regex, subst).trim();
console.log(result);