On 16 August 2012 00:35, Rick Waldron <[email protected]> wrote: > On Wed, Aug 15, 2012 at 6:02 PM, Erik Reppen <[email protected]> wrote: >> >> This topic has probably been beaten to death years before I was even aware >> of es-discuss but it continues to get mentioned occasionally as a point of >> pain so I thought I'd see if I couldn't attempt to hatch a conversation and >> maybe understand the design concerns better than I likely do now. >> >> >> Consistent Type Return for Pass and Fail? >> >> The principle of consistent type-return has occasionally skewered me as >> somebody who came to non-amateur levels of understanding code primarily >> through JavaScript. I can see the value in maintaining consistent types for >> positive results but not so much for indicators that you didn't get anything >> useful. For instance: >> >> * [0,1].indexOf('wombat'); //returns an index on success or -1 to >> indicate failure. -1 passed on to a lot of other array methods of course, >> indicates the last element. If you'd asked me the day I made that mistake I >> could have told you indexOf probably returns -1 on failure to find something >> but it didn't occur to me in the moment. > > It would be far worse to have a different type of value as a return, right?
Actually, no. It is far better to have something that produces failure as immediately and as reliably as possible when used improperly. Sentinel values are a prominent anti-pattern. However, I agree that there is no chance of fixing that for existing libraries. /Andreas _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
