using -> for concise functions and => for TCP functions

short-functions.js

// non-TCP, shorter function
a.some((x) → {
    if (invalid(x))
        return true;
    console.log(x);
})

// maximally concise, implicit return
a.map((x) → x * 17)

// preserves this-binding
CSVReader.prototype.read = function(str) {
    return str.split(/\n/)
              .map((line) → line.split(this.regexp));
};

// using loop controls from within TCP functions
// compare and contrast with: https://gist.github.com/1609202
Mailbox.prototype.extractContents = function(contacts) {
    for (let a = this.messages, i = 0, n = a.length; i < n; i++) {
        a[i].headers.forEach((header) → do {
            if (header.isSpam())
                continue; // could use a label but unnecessary
            let addresses = header.extractAddresses();
            addresses.forEach((addr) → {
                contacts.add(addr.name, addr.email);
            });
        });
    }
};