Eliminate newlines in google app script using regex - regex

Question

I'm trying to write part of an add-on for Google Docs that eliminates newlines within selected text using replaceText. The obvious text.replaceText("\n",""); gives the error Invalid argument: searchPattern. I get the same error with text.replaceText("\r","");. The following attempts do nothing: text.replaceText("/\n/","");, text.replaceText("/\r/","");. I don't know why Google App Script does not allow for the recognition of newlines in regex.
I am aware that there is an add-on that does this already, but I want to incorporate this function into my add-on.
This error occurs even with the basic
DocumentApp.getActiveDocument().getBody().textReplace("\n","");
My full function:
function removeLineBreaks() {
var selection = DocumentApp.getActiveDocument().getSelection();
if (selection) {
var elements = selection.getRangeElements();
for (var i = 0; i < elements.length; i++) {
var element = elements[i];
// Only deal with text elements
if (element.getElement().editAsText) {
var text = element.getElement().editAsText();
if (element.isPartial()) {
text.replaceText("\n","");
}
// Deal with fully selected text
else {
text.replaceText("\n","");
}
}
}
}
// No text selected
else {
DocumentApp.getUi().alert('No text selected. Please select some text and try again.');
}
}

Answer 1

It seems that in replaceText, to remove soft returns entered with Shift-ENTER, you can use \v:
.replaceText("\\v+", "")
If you want to remove all "other" control characters (C0, DEL and C1 control codes), you may use
.replaceText("\\p{Cc}+", "")
Note that the \v pattern is a construct supported by JavaScript regex engine, and is considered to match a vertical tab character (≡ \013) by the RE2 regex library used in most Google products.

Answer 2

The Google Apps Script function replaceText() still doesn't accept escape characters, but I was able to get around this by using getText(), then the generic JavaScript replace(), then setText():
var doc = DocumentApp.getActiveDocument();
var body = doc.getBody();
var bodyText = body.getText();
//DocumentApp.getUi().alert( "Does document contain \\t? " + /\t/.test( bodyText ) ); // \n true, \r false, \t true
bodyText = bodyText.replace( /\n/g, "" );
bodyText = bodyText.replace( /\t/g, "" );
body.setText( bodyText );
This worked within a Doc. Not sure if the same is possible within a Sheet (and, even if it were, you'd probably have to run this once cell at a time).

Answer 3

here is my pragmatic solution to eliminate newlines in Google Docs, or, more exact, to eliminate newlines from Gmail message.getPlainBody().
It looks that Google uses '\r\n\r\n' as a plain EOL and '\r\n' as a manuell Linefeed (Shift-Enter). The code should be self explainable.
It might help to get alone with the newline problem in Docs.
A solution possibly not very elegant, but works like a charm :-)
function GetEmails2Doc() {
var doc = DocumentApp.getActiveDocument();
var body = doc.getBody();
var pc = 0; // Paragraph Counter
var label = GmailApp.getUserLabelByName("_Send2Sheet");
var threads = label.getThreads();
var i = threads.length;
// LOOP Messages within a THREAT
for (i=threads.length-1; i>=0; i--) {
for (var j = 0; j < messages.length; j++) {
var message = messages[j];
/* Here I do some ...
body.insertParagraph(pc++, Utilities.formatDate(message.getDate(), "GMT",
"dd.MM.yyyy (HH:mm)")).setHeading(DocumentApp.ParagraphHeading.HEADING4)
str = message.getFrom() + ' to: ' + message.getTo();
if (message.getCc().length >0) str = str + ", Cc: " + message.getCc();
if (message.getBcc().length >0) str = str + ", Bcc: " + message.getBcc();
body.insertParagraph(pc++,str);
*/
// Body !!
var str = processBody(message.getPlainBody()).split("pEOL");
Logger.log(str.length + " EOLs");
for (var k=0; k<str.length; k++) body.insertParagraph(pc++,str[k]);
}
}
}
function processBody(tx) {
var s = tx.split(/\r\n\r\n/g);
// it looks like message.getPlainBody() [of mail] uses \r\n\r\n as EOL
// so, I first substitute the 'EOL's with the string pattern "pEOL"
// to be replaced with body.insertParagraph in the main function
tx = '';
for (k=0; k<s.length; k++) tx = tx + s[k] + "pEOL";
// then replace all remaining simple \r\n with a blank
s = tx.split(/\r\n/g);
tx = '';
for (k=0; k<s.length; k++) tx = tx + s[k] + " ";
return tx;
}

Answer 4

I have now found out through much trial and error -- and some much needed help from Wiktor Stribiżew (see other answer) -- that there is a solution to this, but it relies on the fact that Google Script does not recognise \n or \r in regex searches. The solution is as follows:
function removeLineBreaks() {
var selection = DocumentApp.getActiveDocument()
.getSelection();
if (selection) {
var elements = selection.getRangeElements();
for (var i = 0; i < elements.length; i++) {
var element = elements[i];
// Only deal with text elements
if (element.getElement()
.editAsText) {
var text = element.getElement()
.editAsText();
if (element.isPartial()) {
var start = element.getStartOffset();
var finish = element.getEndOffsetInclusive();
var oldText = text.getText()
.slice(start, finish);
if (oldText.match(/\r/)) {
var number = oldText.match(/\r/g)
.length;
for (var j = 0; j < number; j++) {
var location = oldText.search(/\r/);
text.deleteText(start + location, start + location);
text.insertText(start + location, ' ');
var oldText = oldText.replace(/\r/, ' ');
}
}
}
// Deal with fully selected text
else {
text.replaceText("\\v+", " ");
}
}
}
}
// No text selected
else {
DocumentApp.getUi()
.alert('No text selected. Please select some text and try again.');
}
}
Explanation
Google Docs allows searching for vertical tabs (\v), which match newlines.
Partial text is a whole other problem. The solution to dealing with partially selected text above finds the location of newlines by extracting a text string from the text element and searching in that string. It then uses these locations to delete the relevant characters. This is repeated until the number of newlines in the selected text has been reached.

Answer 5

This Stack Overflow answer removes, specifically, "\n". It may help, it helped me indeed.