parsePattern.js

// https://github.com/angular/angular.js/blob/5a60302389162c6ef45f311c1aaa65a00d538c66/i18n/src/parser.js
// e.g. '#,##0.###'
function parsePattern(pattern) {
	var p = {
		minInt: 1,
		minFrac: 0,
		maxFrac: 0,
		posPre: '',
		posSuf: '',
		negPre: '',
		negSuf: '',
		gSize: 0,
		lgSize: 0
	};
	
	var parts = pattern.split(PATTERN_SEP),
		positive = parts[0],
		negative = parts[1];
	
	parts = positive.split(DECIMAL_SEP);
	var integer = parts[0],
		fraction = parts[1];
	
	p.posPre = integer.substr(0, integer.indexOf(DIGIT));
	
	for (var i = 0; i < fraction.length; i++) {
		var ch = fraction.charAt(i);
		if (ch === ZERO) { p.minFrac = p.maxFrac = i + 1; }
		else if (ch === DIGIT) { p.maxFrac = i + 1; }
		else { p.posSuf += ch; }
	}
	
	var groups = integer.split(GROUP_SEP);
	p.gSize = groups[1] ? groups[1].length : 0;
	p.lgSize = groups[2] || groups[1] ? (groups[2] || groups[1]).length : 0;
	
	if (negative) {
		var trunkLen = positive.length - p.posPre.length - p.posSuf.length,
			pos = negative.indexOf(DIGIT);
	
		p.negPre = negative.substr(0, pos).replace(/\'/g, '');
		p.negSuf = negative.substr(pos + trunkLen).replace(/\'/g, '');
	} else {
		// hardcoded '-' sign is fine as all locale use '-' as MINUS_SIGN. (\u2212 is the same as '-')
		p.negPre = p.posPre + '-';
		p.negSuf = p.posSuf;
	}
	
	return p;
}