Try to run examples - vain

[chuve]

Trace after run /example/stylus.js

{ [TypeError: /Users/echuvelev/Development/hospital/express/node_modules/stylus/lib/functions/index.styl:286:14
   282|
   283|     &,
   284|     /$cache_placeholder_for_{$id}
   285|       $stylus_mixin_cache[$key] = $id
   286|       {block}
---------------------^
   287|

Cannot read property 'length' of undefined
    at "#smallSquare" (/Users/echuvelev/Development/hospital/express/node_modules/node-sprite/example/sprite.styl:2:1)
]
  lineno: 286,
  column: 14,
  filename: '/Users/echuvelev/Development/hospital/express/node_modules/stylus/lib/functions/index.styl',
  stylusStack: '    at "#smallSquare" (/Users/echuvelev/Development/hospital/express/node_modules/node-sprite/example/sprite.styl:2:1)',
  input: 'called-from = ()\n\nvendors = moz webkit o ms official\n\n// stringify the given arg\n\n-string(arg)\n  type(arg) + \' \' + arg\n\n// require a color\n\nrequire-color(color)\n  unless color is a \'color\'\n    error(\'RGB or HSL value expected, got a \' + -string(color))\n\n// require a unit\n\nrequire-unit(n)\n  unless n is a \'unit\'\n    error(\'unit expected, got a \' + -string(n))\n\n// require a string\n\nrequire-string(str)\n  unless str is a \'string\' or str is a \'ident\'\n    error(\'string expected, got a \' + -string(str))\n\n// Math functions\n\nabs(n) { math(n, \'abs\') }\nmin(a, b) { a < b ? a : b }\nmax(a, b) { a > b ? a : b }\n\n// Trigonometrics\nPI = -math-prop(\'PI\')\n\nradians-to-degrees(angle)\n  angle * (180 / PI)\n\ndegrees-to-radians(angle)\n  unit(angle * (PI / 180),\'\')\n\nsin(n)\n  n = degrees-to-radians(n) if unit(n) == \'deg\'\n  round(math(n, \'sin\'), 9)\n\ncos(n)\n  n = degrees-to-radians(n) if unit(n) == \'deg\'\n  round(math(n, \'cos\'), 9)\n\n// Rounding Math functions\n\nceil(n, precision = 0)\n  multiplier = 10 ** precision\n  math(n * multiplier, \'ceil\') / multiplier\n\nfloor(n, precision = 0)\n  multiplier = 10 ** precision\n  math(n * multiplier, \'floor\') / multiplier\n\nround(n, precision = 0)\n  multiplier = 10 ** precision\n  math(n * multiplier, \'round\') / multiplier\n\n// return the sum of the given numbers\n\nsum(nums)\n  sum = 0\n  sum += n for n in nums\n\n// return the average of the given numbers\n\navg(nums)\n  sum(nums) / length(nums)\n\n// return a unitless number, or pass through\n\nremove-unit(n)\n  if typeof(n) is "unit"\n    unit(n, "")\n  else\n    n\n\n// convert a percent to a decimal, or pass through\n\npercent-to-decimal(n)\n  if unit(n) is "%"\n    remove-unit(n) / 100\n  else\n    n\n\n// check if n is an odd number\n\nodd(n)\n  1 == n % 2\n\n// check if n is an even number\n\neven(n)\n  0 == n % 2\n\n// check if color is light\n\nlight(color)\n  lightness(color) >= 50%\n\n// check if color is dark\n\ndark(color)\n  lightness(color) < 50%\n\n// desaturate color by amount\n\ndesaturate(color, amount)\n  adjust(color, \'saturation\', - amount)\n\n// saturate color by amount\n\nsaturate(color = \'\', amount = 100%)\n  if color is a \'color\'\n    adjust(color, \'saturation\', amount)\n  else\n    unquote( "saturate(" + color + ")" )\n\n// darken by the given amount\n\ndarken(color, amount)\n  adjust(color, \'lightness\', - amount)\n\n// lighten by the given amount\n\nlighten(color, amount)\n  adjust(color, \'lightness\', amount)\n\n// decrease opacity by amount\n\nfade-out(color, amount)\n  color - rgba(black, percent-to-decimal(amount))\n\n// increase opacity by amount\n\nfade-in(color, amount)\n  color + rgba(black, percent-to-decimal(amount))\n\n// spin hue by a given amount\n\nspin(color, amount)\n  color + unit(amount, deg)\n\n// mix two colors by a given amount\n\nmix(color1, color2, weight = 50%)\n  unless weight in 0..100\n    error("Weight must be between 0% and 100%")\n\n  if length(color1) == 2\n    weight = color1[0]\n    color1 = color1[1]\n\n  else if length(color2) == 2\n    weight = 100 - color2[0]\n    color2 = color2[1]\n\n  require-color(color1)\n  require-color(color2)\n\n  p = unit(weight / 100, \'\')\n  w = p * 2 - 1\n\n  a = alpha(color1) - alpha(color2)\n\n  w1 = (((w * a == -1) ? w : (w + a) / (1 + w * a)) + 1) / 2\n  w2 = 1 - w1\n\n  channels = (red(color1) red(color2)) (green(color1) green(color2)) (blue(color1) blue(color2))\n  rgb = ()\n\n  for pair in channels\n    push(rgb, floor(pair[0] * w1 + pair[1] * w2))\n\n  a1 = alpha(color1) * p\n  a2 = alpha(color1) * (1 - p)\n  alpha = a1 + a2\n\n  rgba(rgb[0], rgb[1], rgb[2], alpha)\n\n// invert colors, leave alpha intact\n\ninvert(color = \'\')\n  if color is a \'color\'\n    rgba(#fff - color, alpha(color))\n  else\n    unquote( "invert(" + color + ")" )\n\n// give complement of the given color\n\ncomplement( color )\n  spin( color, 180 )\n\n// give grayscale of the given color\n\ngrayscale( color = \'\' )\n  if color is a \'color\'\n    desaturate( color, 100% )\n  else\n    unquote( "grayscale(" + color + ")" )\n\n// mix the given color with white\n\ntint( color, percent )\n  mix( white, color, percent )\n\n// mix the given color with black\n\nshade( color, percent )\n  mix( black, color, percent )\n\n// return the last value in the given expr\n\nlast(expr)\n  expr[length(expr) - 1]\n\n// return keys in the given pairs or object\n\nkeys(pairs)\n  ret = ()\n  if type(pairs) == \'object\'\n    for key in pairs\n      push(ret, key)\n  else\n    for pair in pairs\n      push(ret, pair[0]);\n  ret\n\n// return values in the given pairs or object\n\nvalues(pairs)\n  ret = ()\n  if type(pairs) == \'object\'\n    for key, val in pairs\n      push(ret, val)\n  else\n    for pair in pairs\n      push(ret, pair[1]);\n  ret\n\n// join values with the given delimiter\n\njoin(delim, vals...)\n  buf = \'\'\n  vals = vals[0] if length(vals) == 1\n  for val, i in vals\n    buf += i ? delim + val : val\n\n// add a CSS rule to the containing block\n\n// - This definition allows add-property to be used as a mixin\n// - It has the same effect as interpolation but allows users\n//   to opt for a functional style\n\nadd-property-function = add-property\nadd-property(name, expr)\n  if mixin\n    {name} expr\n  else\n    add-property-function(name, expr)\n\nprefix-classes(prefix)\n  -prefix-classes(prefix, block)\n\n// Caching mixin, use inside your functions to enable caching by extending.\n\n$stylus_mixin_cache = {}\ncache()\n  $key = (current-media() or \'no-media\') + \'__\' + called-from[0] + \'__\' + arguments\n  if $key in $stylus_mixin_cache\n    @extend {"$cache_placeholder_for_" + $stylus_mixin_cache[$key]}\n  else if \'cache\' in called-from\n    {block}\n  else\n    $id = length($stylus_mixin_cache)\n\n    &,\n    /$cache_placeholder_for_{$id}\n      $stylus_mixin_cache[$key] = $id\n      {block}\n' }
undefined
watching for file changes in './images' ...