Unicode Fractions

script

// do the actual replacing
function replacer( match, cg1, cg2 ) {
	return cg1.concat( fractions[ cg2 ] );
}

// regexp to match fractions that have unicode equivalents
const needle = new RegExp(
	/(^| |\t)((0\/3)|(1\/([2-9]|10))|(2\/[3,5])|(3\/[4,5,8])|(4\/5)|(5\/[6,8])|(7\/8))(?![0-9])/,
	'gim'
);

// associative array of unicode fractions
const fractions = {
	'0/3': '↉',
	'1/2': '½',
	'1/3': '⅓',
	'1/4': '¼',
	'1/5': '⅕',
	'1/6': '⅙',
	'1/7': '⅐',
	'1/8': '⅛',
	'1/9': '⅑',
	'1/10': '⅒',
	'2/3': '⅔',
	'2/5': '⅖',
	'3/4': '¾',
	'3/5': '⅗',
	'3/8': '⅜',
	'4/5': '⅘',
	'5/6': '⅚',
	'5/8': '⅝',
	'7/8': '⅞'
};

// replace fractions with their unicode equivalent
editor.setText( editor.getText().replace( needle, replacer ) );