Another way to look at it ; Butlast purpose discard the last N input title(s)
So saying "discard the last 0 input titles" is non sensical If you actually want to discard 3, then 2 then 1 perhaps you filter needs find another way once it reaches 0 Tones On Monday, 28 June 2021 at 13:07:37 UTC+10 History Buff wrote: > Thanks Eric, > > I appreciate that. I looked at it, but I really don’t know JavaScript. > Makes me want to learn though. > > > > On Sun, Jun 27, 2021 at 12:07 PM Eric Shulman <elsd...@gmail.com> wrote: > >> On Sunday, June 27, 2021 at 11:28:50 AM UTC-7 History Buff wrote: >> >>> I don't understand why a 0 in the butlast operator would yield no results >>> >> >> The butlast[] operator is defined in this shadow tiddler: >> https://tiddlywiki.com/#%24%3A%2Fcore%2Fmodules%2Ffilters%2Flistops.js >> >> Here's the javascript code from that tiddler: >> exports.butlast = function(source,operator,options) { >> var count = $tw.utils.getInt(operator.operand,1), >> results = []; >> source(function(tiddler,title) { >> results.push(title); >> }); >> return results.slice(0,-count); >> }; >> >> The first line gets the operand value, defaulting to 1. >> The next 4 lines copy the entire list of items into a results array >> The last line uses the javascript slice() function to remove items from >> the results array and then return that array >> >> Here's the documentation for the javascript slice() function: >> >> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/slice >> >> Note the description of the "end" parameter: >> Zero-based index before which to end extraction. slice extracts up to *but >> not including* end. >> >> Thus, when you used butlast[0], the filter code invokes slice(0,-0), >> i.e., "*starting from the first item up to but not including the first >> item*" >> which results in *no items* being returned. >> >> enjoy, >> -e >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "TiddlyWiki" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/tiddlywiki/lROJc--2xFI/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> tiddlywiki+...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/tiddlywiki/c1f40a73-746d-4c39-89b9-6786c9caee0fn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/tiddlywiki/c1f40a73-746d-4c39-89b9-6786c9caee0fn%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To unsubscribe from this group and stop receiving emails from it, send an email to tiddlywiki+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/tiddlywiki/faaa280d-a866-47d3-abef-5ec8e51e5d5dn%40googlegroups.com.
