Common NSDate formats and helpers

NSDate+Formats.h

//
//  NSDate+Formats.h
//  Rego
//
//  Created by Justin Driscoll on 12/7/12.
//  Copyright (c) 2012 Makalu Inc. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSDate (Formats)

+ (NSDate *)fromJSONDate:(NSString *)aJSONDate;
- (NSString *)localizedString;
- (NSString *)localizedStringWithTime;
- (NSString *)toJSONDate;
- (NSString *)stringWithFormat:(NSString *)format;

@end

NSDate+Formats.m

//
//  NSDate+Formats.m
//  Rego
//
//  Created by Justin Driscoll on 12/7/12.
//  Copyright (c) 2012 Makalu Inc. All rights reserved.
//

#import "NSDate+Formats.h"

@implementation NSDate (Formats)

- (NSString *)localizedString
{
    static NSDateFormatter *dateFormatter = nil;
    if (dateFormatter == nil) {
        dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setLocale:[NSLocale currentLocale]];
        [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
        [dateFormatter setTimeStyle:NSDateFormatterNoStyle];
    }

    return [dateFormatter stringFromDate:self];
}

- (NSString *)localizedStringWithTime
{
    static NSDateFormatter *dateFormatter = nil;
    if (dateFormatter == nil) {
        dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setLocale:[NSLocale currentLocale]];
        [dateFormatter setDateStyle:NSDateFormatterLongStyle];
        [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
    }

    return [dateFormatter stringFromDate:self];
}

- (NSString *)toJSONDate
{
    return [self stringWithFormat:@"yyyy-MM-dd'T'HH:mm:ss'Z'"];
}

+ (NSDate *)fromJSONDate:(NSString *)aJSONDate
{
    static NSDateFormatter *formatter = nil;
    if (formatter == nil) {
        formatter = [[NSDateFormatter alloc] init];
        [formatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss'Z'"];
    }
    return [formatter dateFromString:aJSONDate];
}


- (NSString *)stringWithFormat:(NSString *)format
{
    static NSDateFormatter *dateFormatter = nil;
    if (dateFormatter == nil) {
        dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];
    }
    dateFormatter.dateFormat = format;
    return [dateFormatter stringFromDate:self];
}

@end