• Version: 10.13 (also 8.x and before)
• Platform: Windows
• Subsystem: fs

The following snipped works fine on Linux and Mac OS X, but not on Windows:

const fs = require('fs')
const str = 'èè'
fs.write(1, str + '\n', 0, '', console.log)

Note that using process.stdout.write is actually working as expected.