index.js
function def (params, spec, errs) {
  for (var key in params) {
    if (!spec.hasOwnProperty(key)) defError(key, errs)
  }
}
function def (params, spec, errs) {
  for (var key in params) {
    if (!spec.hasOwnProperty(key)) defError(key, errs)
  }
}
function def ( params , spec , errs ) { for ( var key in params ) { if ( ! spec . hasOwnProperty ( key ) ) defError ( key , errs ) } }
Ensure that parameter is defined.

@param {Object} params
Parameters value object.

@param {String} spec
Parameters definition object.

@param {Array} errs
Errors list.
Ensure that parameter is defined .