On Feb 19, 2014 12:17 PM, "Domenic Denicola" <domenic@domenicdenicola.com> wrote: > > I think in general functions that treat not-passed as different from undefined are *very* surprising and un-JavaScript-ey; I feel like we've discussed this on this list many times before. `arguments.length` is the only way to create such functions, and that will be even less possible in ES6 given the function forms for which `arguments` is not present. > > I don't know what behavior is most appropriate for `postMessage()` but it should be the same as the behavior for `postMessage(undefined)`. Rather than talk in generalities, I'd really prefer to talk about specific examples. `postMessage(x)` sends the javascript value in x to the receiver. Our aim has been that any values other than callable objects are valid values. `cursor.update(x)` saves the javascript value in x to the database. Our aim has been that any values other than callable objects are valid values. What behaviour do we want in these two specific cases when x is omitted. I.e. what makes the best API. I can both see the argument "if you were to naively implement this in JS omitting x should be equivalent to x === undefined" and "omitting x is clearly a bug, throw an exception". I just don't know which argument is stronger. / Jonas
Received on Wednesday, 19 February 2014 21:31:00 UTC