Unnecessary code in bundles

[Loskir]

Due to the lack of PURE annotations, extra code is included in bundles. Example: var tokens = new Map(...) is included and immediately thrown away (tokens var is not used, but the bundler is not sure if new Map can be safely omitted).

As I suppose tokens is indeed pure, this issue can be fixed by adding a few /* @__PURE__ */ annotations like this:

tempo/src/common.ts

Line 89 in 28a9539

export const tokens = new Map(

export const tokens = /* @__PURE__ */ new Map(
  /* @__PURE__ */ [...clockAgnostic, ...clock24, ...clock12].map((format) => {
    return [format[0], format]
  }),
)

More info:
Bundler — vite 5.1.4

[WilcoSp]

I also experience this with Vite not being able to treeshake tempo.
currently I use format & parse in a vue component but when I check the compiled source I'm also able to find other tempo functions in it

[justin-schroeder]

@WilcoSp can you identify if those functions are being used in format/parse? In general everything should be able to tree shake pretty well, perhaps with the exception of this issue (Map) which we can annotate. format/parse are the largest functions in the library as you might imagine, and they do use some of the functions in the library.

[WilcoSp]

with esBuilds 'keepNames' settings I was able to identify the following functions being bundled in:

• iso8601 (date)

• normalize (date)

• date (format/parse/offset)

• monthEnd (monthDays)

• monthDays (parse)

• fixedLengthByOffset (parse)

• normStr (ap)

• fill (format)

• createPartMap (fill)

• minsToOffset (offset)

• offsetToMins (applyOffset)

• validOffset (parse)

• escapeTokens (formatStr)

• isNumeric (validate)

• validate (parse)

• ap (parse, range)

• applyOffset (applyOffset)

• deviceTZ (format)

• relativeTime (offset)

• offset (format)

• parts (format/parse)

• styleParts (parts)

• guessPattern (styleParts)

• partStyle (guessPattern)

• removeOffset (format)

• deviceLocale (format)

• formatStr (parse)

• fourDigitYear (parse)

• range (parse)

• parseParts (parse)

• format (by range)

bold are directly imported by parse/format
italic are used by imported functions of parse/format
between () is by which function(s) it gets used

after doing this it does seem everything gets used when using parse/format. but I do wonder how the bundle size does get around the +-12kb (not gzipped), +-5kb gzipped.

sorry about what I had said about not being tree shakable, but what might had happened yesterday is that vite wasn't able to split tempo when using "addSecond" at a file that gets bundled into index.js, while for example date-fns was able to be split by vite

[WilcoSp]

tomorrow I'll make an example vue project to replicate the splitting issue

[WilcoSp]

I've created the repo to test splitting of Tempo with Vite and documented what I've observed into the readme

@justin-schroeder this may help to get Tempo into smaller bundles with at least Vite

link: https://github.com/WilcoSp/tempo-split-test