I need help to replace a newline with space in a string with double quotes and value between.

This is my current expression but it's only replace newline if string doesn't contain any other value.

/"([\r\n]*?)"/g

I want to change this:

• "Log field with multiple lines.

  This is now fixed."

For this:

• "Log field with multiple lines. This is now fixed."

I need help to replace a newline with space in a string with double quotes and value between.

This is my current expression but it's only replace newline if string doesn't contain any other value.

/"([\r\n]*?)"/g

I want to change this:

• "Log field with multiple lines.

  This is now fixed."

For this:

• "Log field with multiple lines. This is now fixed."

• javascript
• regex

• 2 Can the substrings in between " contain escaped literal " chars? Can there be multiple line breaks in between the quotation marks? – Wiktor Stribiżew Commented Dec 14, 2018 at 9:21
• For now, no. I collect data from csv file and then search for place where is unwanted newline between double quotes. – Aleksander Karp Commented Dec 14, 2018 at 9:25
• 1 Doesn't that mean that literal " are represented with ""? It is important to know how to detect the open and close "s between which you want to remove line breaks. – Wiktor Stribiżew Commented Dec 14, 2018 at 9:26
• 1 Try s.replace(/"(?:""|[^"])+"/g, function(x) { return x.replace(/[\r\n]+/g, ' ');}), see demo. – Wiktor Stribiżew Commented Dec 14, 2018 at 9:31

3 Answers 3

To remove all chunks of line break chars in between double quotation marks, you need to match these substrings between the qualifying start and end double quotation marks. Thus, it is crucial to know if " chars can appear escaped in between the " delimiters.

In a CSV, the literal double quotation marks are usually doubled. Then, you may use

var s = '"Cell1","Cell\r\n#2","""Cell #3\r\nhere\nand there"""';
s = s.replace(/"(?:""|[^"])+"/g, function(x) { return x.replace(/[^\S\r\n]*[\n\r]\s*/g, ' ');});
console.log(s);

The "(?:""|[^"])+"/g regex matches a ", then 1 or more occurrences of "" substring or any char other than ", and then ". When the match is found, all CR and LF symbols with any 0+ whitespaces before and after them are removed using a simple .replace(/[^\S\r\n]*[\n\r]\s*/g, ' ') replace operation.

If the literal double quotation marks are escaped with a backslash, you may use

/"[^"\\]*(?:\\[\s\S][^"\\]*)*"/g

If you are sure there are no escaped double quotation marks, use

/"[^"]+"/g

You could use a function within .replace() like this:

var data = `
I need help to replace a newline with space in a string with double quotes and value between.

This is my current expression but it's only replace newline if string doesn't contain any other value.

I want to change this:

    "Log field with multiple lines.

    This is now fixed."

For this:

    "Log field with multiple lines. This is now fixed."
`;

var regex = /"[^"]*"/g;

data = data.replace(regex, function (match, capture) { 
    return match.replace(/[\n\r]\s*/g, " ");
}); 
console.log(data);

First, it looks for anything bewteen dobule quotes, second is removes newlines and possible consecutive whitespaces thereafter. The approach won't work with escaped quotes though.

This should solve your problem:

/\r\n|\r|\n/g

1st Alternative \r\n

\r matches a carriage return (ASCII 13) \n matches a line-feed (newline) character (ASCII 10)

2nd Alternative \r

\r matches a carriage return (ASCII 13)

3rd Alternative \n

\n matches a line-feed (newline) character (ASCII 10)

g modifier

All matches (don't return after first match)