Word wrap string

JavaScript, String, Regexp · Oct 22, 2020

Wraps a string to a given number of characters using a string break character.

Use String.prototype.replace() and a regular expression to insert a given break character at the nearest whitespace of max characters.
Omit the third argument, br, to use the default value of '\n'.

const wordWrap = (str, max, br = '\n') => str.replace(
  new RegExp(`(?![^\\n]{1,${max}}$)([^\\n]{1,${max}})\\s`, 'g'), '$1' + br
);

wordWrap(
  'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce tempus.',
  32
);
// 'Lorem ipsum dolor sit amet,\nconsectetur adipiscing elit.\nFusce tempus.'
wordWrap(
  'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce tempus.',
  32,
  '\r\n'
);
// 'Lorem ipsum dolor sit amet,\r\nconsectetur adipiscing elit.\r\nFusce tempus.'