add custom function to stylus with javascript api

Question

I want to add the charAt js function to stylus and i try the example posted in the stylus docs, is as follows:

var stylus = require('./node_modules/stylus')
, nodes = stylus.nodes
, utils = stylus.utils
, fs = require('fs');

function charAt(string, index) {
  return string.charAt(index);
}


stylus(str)
  .set('filename', 'js-functions')
  .define('charAt', charAt)

  .render(function(err, css){
    if (err) throw err;
    console.log(css);
  });

I change the require path to my stylus dir and inside test.styl i have the following:

use('js-functions.js')

when i run it a take the error:

ReferenceError: test.styl:1
  > 1| use("js-functions.js")
    2| 
    3| 
    4| 

str is not defined

What is happening here?, what i a missing?, the docs not explain it very well for people who are new to node and stylus.

Answer 1

create a file 'test.js' like this:

var plugin = function(){
    return function(style){
        style.define('charAt', function (string, index) {

        })
    }
}
module.exports = plugin;

stylus code:

use('test.js')