Simple promise.fold usage example

fold.js

// Should log:
// 3
// Bob
// b

var when = require('when');

when.resolve(1).fold(sum, 2).done(console.log);

when.resolve({ name: 'Bob' }).fold(get, 'name').done(console.log);

when.resolve(['a', 'b', 'c']).fold(get, 1).done(console.log);

function sum(x, y) {
	return x + y;
}

function get(k, o) {
	return o[k];
}