How to Remove all Line Breaks from a String in JavaScript

Table of Contents #

1. Remove all Line Breaks from a String in JavaScript
2. Remove Line Breaks from Start and End of a String in JavaScript
3. Remove all line breaks and replace multiple spaces with a single space
4. Remove Line Breaks from the Start and End of a String using regex

Remove all Line Breaks from a String in JavaScript #

Use the String.replace() method to remove all line breaks from a string, e.g. str.replace(/[\r\n]/gm, '');.

The replace() method will remove all line breaks from the string by replacing them with empty strings.

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const str = 'a\n multi \n line \r string \n!';

// ✅ Remove all line breaks from string
const withoutLineBreaks = str.replace(/[\r\n]/gm, '');
console.log(withoutLineBreaks); // 👉️ a multi line string !

// -----------------------------------------------------

// ✅ Remove only line breaks from the start and end of the string

const str2 = '\nbobby hadz\n';
const result = str2.trim();

console.dir(result); // 👉️ 'bobby hadz'

The String.replace() method returns a new string with one, some, or all matches of a regular expression replaced with the provided replacement.

The method takes the following parameters:

We passed a regular expression to the String.replace() method.

Let's first cover the g and m flags at the end of the regex.

The g (global) flag is used to specify that we want to match all occurrences of the regex and not just the first occurrence.

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const str = 'a\n multi \n line \r string \n!';

const withoutLineBreaks = str.replace(/[\r\n]/gm, '');
console.log(withoutLineBreaks); // 👉️ a multi line string !

The m (multiline) flag is used to specify that we want to match occurrences over multiple lines.

The square brackets [] are called a character class and are used to match either of the characters between the brackets.

We want to replace both \r and \n because line breaks vary depending on the operating system.

The second parameter we passed to the String.replace() method is the replacement for each match.

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const str = 'a\n multi \n line \r string \n!';

const withoutLineBreaks = str.replace(/[\r\n]/gm, '');
console.log(withoutLineBreaks); // 👉️ a multi line string !

For our purposes, we replace each occurrence of a line break with an empty string to remove the line breaks.

The String.replace() method returns a new string with the matches of the pattern replaced. The method doesn't change the original string.

Strings are immutable in JavaScript.

Remove Line Breaks from Start and End of a String in JavaScript #

If your string only has leading and trailing new lines, you can also use the String.trim() method.

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const str = '\n\r\na multi line string!\n\r\n';

const result = str.trim();
console.log(result); // 👉️ a multi line string!

The String.trim() method removes the leading and trailing whitespace from a string including newline characters.

Note that the String.trim() approach wouldn't remove the line breaks in the middle of the string.

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const str = '\n\r\na multi \nline string!\n\r\n';

// a multi
// line string!
const result = str.trim();
console.log(result);

The String.trim() method removed the leading and trailing newline characters, but not the one in the middle of the string.

Remove all line breaks and replace multiple spaces with a single space #

If you need to remove all line breaks in the string and replace multiple spaces with a single space, use the following regular expression.

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const str = 'a\n     multi   \n   line   \r   string';

const result = str.replace(/\s+/g, ' ').trim();
console.dir(result); // 👉️ 'a multi line string'

We used the \s character in the regex. The special character matches spaces, tabs and new lines.

The plus + matches the preceding item (whitespace characters and newline (\n) characters) 1 or more times.

The g (global) flag is used to specify that we want to match all occurrences of the regex and not just the first occurrence.

In its entirety, the regular expression replaces one or more spaces and line breaks with a single space.

The last step is to use the String.trim() method to remove any leading and trailing whitespace.

Remove Line Breaks from the Start and End of a String using regex #

To remove the line breaks from the start and end of a string:

1. Call the replace() method with the following regular expression - /^\s+|\s+$/g.
2. The regular expression matches any leading or trailing new lines.
3. Provide an empty string as the replacement for each match.

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const str = '\none two\n';

const result = str.replace(/^\s+|\s+$/g, '');
console.log(result); // 👉️ "one two"

The String.replace() method returns a new string with one, some, or all matches of a regular expression replaced with the provided replacement.

The method takes the following parameters:

The forward slashes / / mark the beginning and end of the regular expression.

The caret ^ and dollar sign $ match the beginning and end of the input.

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const str = '\none two\n';

const result = str.replace(/^\s+|\s+$/g, '');
console.log(result); // 👉️ "one two"

The \s special character matches any spaces, tabs or newlines.

The plus + matches the preceding item (the space/tab/newline) one or more times.

If you ever need help reading a regular expression, check out this regular expression cheatsheet by MDN.

It contains a table with the name and the meaning of each special character with examples.