Delta Service

delta.js

/*
 * Checks two Date objects based on human date (mm/dd/yyyy) two test equality
 *
 * @param {Date} date1
 * @param {Date} date2
 * @return {Boolean}
 */
function sameHumanDate(date1, date2){
  if (date1.getDate() === date2.getDate() &&
		date1.getFullYear() === date2.getFullYear() &&
		date1.getMonth() === date2.getMonth()
	){
			return true;
	}
	else {
		return false;
	}
}

/*
 * Gets value of field in object
 *
 * @param {Object} obj
 * @param {String} field - ex: 'effective' or 'rate.effective'
 *
 * @return {Object} value of field
 */
function getValue(obj, field){
  var properties = field.split('.');

	var internal = obj;

	for(var p = 0; p < properties.length; p++){
		internal = internal[properties[p]];
	}

	return internal;
}



/*
 * Checks if delta array is valid
 *
 * @param {Array} deltas
 * @param {String} field
 *
 * @return {Boolean}
 */
function valid(deltas, field){

	if (deltas.length > 1) {

		for (var i=0; i < deltas.length-1; i++) {
			for (var j = i+1; j < deltas.length; j++) { 

				var i_date = getValue(deltas[i], field),
				j_date = getValue(deltas[j], field);

				// ensure no deltas have same date (mm/dd/yyyy)
				if (dateService.sameHumanDate(i_date, j_date)) return false;
			}
		}
	}

	return true;
}

/*
 * Find effective delta for a given date
 *
 * @param {Date} date
 * @param {Array} deltas
 * @param {String} field
 *
 * @return {Object}
 */
function find(date, deltas, field){
	
	if(deltas.length === 0) return null;
	
	// sort deltas by ascending date
	deltas.sort(function(a, b){
		return getValue(a, field).getTime() - getValue(b, field).getTime(); 
	});

	// special case where no effective delta
	if(getValue(deltas[0], field) > date) return null;

	// find most effective delta
	for(var r = 1; r < deltas.length; r++){
		var _deltaDate = getValue(deltas[r], field);
		
		if(dateService.sameHumanDate(_deltaDate, date)) return deltas[r];
		
		if(_deltaDate > date) return deltas[r-1];
	}
	
	// if no deltas end effective period, return last
	return deltas[deltas.length - 1];
}

exports.valid = valid;
exports.find = find;
exports.sameHumanDate = sameHumanDate;