spec/uglify/riot.js
function isWritable(obj, key) {
  var props = Object.getOwnPropertyDescriptor(obj, key)
  return typeof obj[key] === T_UNDEF || props && props.writable
}
function isWritable(obj, key) {
  var props = Object.getOwnPropertyDescriptor(obj, key)
  return typeof obj[key] === T_UNDEF || props && props.writable
}
function isWritable ( obj , key ) { var props = Object . getOwnPropertyDescriptor ( obj , key ) return typeof obj [ key ] === T_UNDEF || props && props . writable }
Detect whether a property of an object could be overridden
@param   { Object }  obj - source object
@param   { String }  key - object property
@returns { Boolean } is this property writable?
Detect whether a property of an object could be overridden