Functions

info

Imported functions are lexical. @-from binds selected names and aliases; @-use binds them through a namespace. Jess has no ambient Less or Sass function namespace. See Modules & imports for the canonical contract.

Import a function, then call its explicit $ binding:

@-from './functions.js' import (double);

.box {
  width: $double(10px);
}

The function receives and returns typed values. A dimension keeps its unit, so the example emits:

.box {
  width: 20px;
}

note

Bare double(10px) is always a CSS-shaped call and remains available to the browser. An import never changes its meaning. Both imported functions and stylesheet-defined functions use explicit $name(…) calls; their definitions come from different places.