@jesscss/fns

@jesscss/fns

The built-in Less/Sass style-function library — color, math, string, and list helpers, split per-file for tree-shaking.

@jesscss/fns is the standard function library for Jess. It provides the built-in functions the language exposes: color operations (lighten, darken, mix, saturate, …), math (round, floor, sqrt, pow, …), unit and type helpers, string helpers, and list/map utilities.

Functions live in their own files and are re-exported from a dialect index, so bundlers can tree-shake down to only the helpers you actually use.

Each dialect owns its globals. A dialect folder's index exports what lives in that folder plus the entries of shared/ that dialect actually has, and that index is simultaneously the importable module and the unit the compiler registers. There is no merged built-in set and no fallback from one dialect to another — a Sass function is never served the Less implementation.

@jesscss/fns              → dialect namespaces (`less`, `sass`, `shared`) + registry helpers
@jesscss/fns/less         → the Less dialect index (the Less built-in set)
@jesscss/fns/less/registry→ `makeLessRegistry()`
@jesscss/fns/sass         → the Sass dialect index (Sass globals)
@jesscss/fns/sass/registry→ `makeSassRegistry()`
@jesscss/fns/sass/color   → sass:color
@jesscss/fns/sass/list    → sass:list
@jesscss/fns/sass/map     → sass:map
@jesscss/fns/sass/math    → sass:math
@jesscss/fns/sass/string  → sass:string
@jesscss/fns/shared       → functions whose behaviour is identical in Less and Sass
@jesscss/fns/registry     → `fnsOf(index)` / `registryOf(index)`

Adding a built-in is a new module in the dialect folder plus one line in that folder's index. Nothing else enumerates the set.

Entries that are still in the legacy tree-node domain remain exported for the JavaScript-callable surface but are not registered as built-ins; converting one in place is what registers it.

The Sass-side helpers exist in the source tree as part of the roadmap Sass+ work, but SCSS is not the focus of the Less-focused alpha — treat that surface as experimental.

Who uses it

This is an internal engine package. The functions are primarily invoked by the compiler during evaluation, and several expect a Jess evaluation context on this — they are not yet a general-purpose, standalone JavaScript API. Most people should install jess and use the jess CLI. The JavaScript/TypeScript API is not yet stabilized.

Status

Alpha. Published to npm under both the latest and alpha dist-tags. Please report bugs.

Links

• Repository: https://github.com/jesscss/jess
• Documentation: https://jesscss.github.io/ (currently pre-alpha content)

License

MIT