code: function getTransformers (opts) {
    var cwd = opts.basedir || process.cwd()
    var transforms = [].concat(opts.transform).filter(Boolean)
    return transforms.map(function (item) {
      // support [ 'brfs', {} ] and 'brfs'
      var transform
      var transformOpts = {}
      if (Array.isArray(item)) {
        transform = item[0]
        transformOpts = item[1] || {}
      } else {
        transform = item
      }
      if (typeof transform === 'string') {
        // resolve module names like in browserify
        var file = resolve.sync(transform, {
          basedir: cwd
        })
        transform = require(file)
        if (typeof transform !== 'function') {
          throw new Error(
            'Transform at ' + file + ' must export a function'
          )
        }
      } else if (typeof transform !== 'function') {
        throw new Error(
          'Expected string or function for transform, got ' + item
        )
      }
      return [ transform, transformOpts ]
    })
  }
docs: -> fn(err, [ [ transformFn, transformOpts ] ])