Node.js - Error: EAGAIN: resource temporarily unavailable, read

EAGAIN code just means: there is nothing to read now and you should try read later.

Example unification for Window and Unix/Linux:

const fs = require('fs');

// Reads bytes into buffer returning -1 when transmission ended.
//
const readSync = (fd, buffer, offset, length) => {
    try {
        const result = fs.readSync(fd, buffer, offset, length);
        return result === 0 ? -1 : result;
    } catch (error) {
        if (error.code === 'EAGAIN') {  // when there is nothing to read at the current time 
            return 0;
        }
        throw error;
    }
};

See also

1. Node.js - read process.stdin using fs.readSync() function (sync reading)

Refrences

1. https://nodejs.org/api/os.html#posix-error-constants