Skip to content
This repository has been archived by the owner on Jan 25, 2019. It is now read-only.


Repository files navigation


About Underscore.m

Underscore.m is a small utility library to facilitate working with common data structures in Objective-C.
It tries to encourage chaining by eschewing the square bracket]]]]]].
It is inspired by the awesome underscore.js.

Real world example

// First, let's compose a twitter search request
NSURL *twitterSearch = [NSURL URLWithString:@""];

// ... then we fetch us some json ...
NSData *data = [NSData dataWithContentsOfURL:twitterSearch];

// ... and parse it.
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data

// This is where the fun starts!
NSArray *tweets = [json valueForKey:@"results"];

NSArray *processed = _array(tweets)
    // Let's make sure that we only operate on NSDictionaries, you never
    // know with these APIs ;-)
    // Remove all tweets that are in English
    .reject(^BOOL (NSDictionary *tweet) {
        return [[tweet valueForKey:@"iso_language_code"] isEqualToString:@"en"];
    // Create a simple string representation for every tweet
    .map(^NSString *(NSDictionary *tweet) {
        NSString *name = [tweet valueForKey:@"from_user_name"];
        NSString *text = [tweet valueForKey:@"text"];

        return [NSString stringWithFormat:@"%@: %@", name, text];


Documentation for Underscore.m can be found on the website.