var stream = require('stream')

function isStream (obj) {

return obj instanceof stream.Stream

}

function isReadable (obj) {

return isStream(obj) && typeof obj._read == 'function' && typeof obj._readableState == 'object'

}

function isWritable (obj) {

return isStream(obj) && typeof obj._write == 'function' && typeof obj._writableState == 'object'

}

function isDuplex (obj) {

return isReadable(obj) && isWritable(obj)

}

module.exports = isStream module.exports.isReadable = isReadable module.exports.isWritable = isWritable module.exports.isDuplex = isDuplex