index.js

'use strict';
var gutil = require('gulp-util');
var through = require('through2');
var assign = require('object-assign');
var customProps = require('custom-props');

module.exports = function (opts) {
  return through.obj(function (file, enc, cb) {
    if (file.isNull()) {
      cb(null, file);
      return;
    }

    if (file.isStream()) {
      cb(new gutil.PluginError('gulp-custom-props', 'Streaming not supported'));
      return;
    }

    var options = assign({}, opts);

    var filePath = file.path;

    try {
      options.name = typeof options.name === 'function' && options.name(file) || file.relative;
      file.contents = new Buffer(customProps(file.contents.toString(), options));
      file.path = gutil.replaceExtension(file.path, '.css');
      this.push(file);
    } catch (err) {
      this.emit('error', new gutil.PluginError('gulp-nunjucks', err, {fileName: filePath}));
    }

    cb();
  });
};