challenge.js

// Parse string +path+ into nested objects within +object+ and assign
// the deepest key to +value+, without overwriting existing keys.
// Examples follow.
function parse(path, value, object) { }

parse("foo", 42, {});                             // => { foo: 42 }
parse("foo.bar", 42, {});                         // => { foo: { bar: 42 } }
parse("foo.bar.baz", 42, {});                     // => { foo: { bar: { baz: 42 } } }
parse("foo", 42, { challenge: "accepted" });      // => { foo: 42, challenge: 'accepted' }
parse("foo.bar", 42, { challenge: "accepted" });  // => { foo: { bar: 42 }, challenge: 'accepted' }
parse("foo", 42, { foo: "accepted" });            // => { foo: 'accepted' }
parse("foo.bar", 42, { foo: { baz: "qux" } });    // => { foo: { baz: 'qux', bar: 42 } }