Short robust library overlies on fs module.

File.js

const fs = require("fs");
const path = require("path");

let file = {
    pipes: [],
    /**
     * Adds new file into pipes as objects which could be later acessed.
     * @param {String} file - Filename to read a specific file.
     * @param {String | Number} mode - Options that how the Interpreter will load the file.
     */
    add: function(file, mode) {
        if(fs.existsSync(file)) {
            var fileSize = fs.statSync(file).size, /* Getting filesize */
                fileBuffer = new Buffer.alloc(fileSize), /* Intializing buffer */
                fd = fs.openSync(path.resolve(file), mode, 0o666); /* Opening file Syncroniously */
            fs.readSync(fd, fileBuffer, 0, fileSize, null); /* Reading file data and storing to a buffer. */

            var fileObject = {
                descriptor: fd,
                buffer: fileBuffer,
                length: fileSize
            }; /* Pushing data to array which could be later acessed. */
            
            this.pipes.push(fileObject);
            return fileObject;
        }
    },
    
    /**
     * Returns file Object using a file descriptor.
     * @param {Number} fd - File Descriptor (aka. File pipe index)
     */
    get: function(fd) {
        if(isNaN(fd)) throw new Error("File descriptor should be a number");
        else if(!isInt(fd)) throw new Error("File descriptor should be integer");
        else {
            this.pipes.find((element) => {
                if(element.descriptor == fd) return element; /* If the descriptor stored in array matches with argument. */
                else throw new Error("Descriptor isn't even opened");
            });
        }
    },


    /**
     * Removes file Object using a file descriptor.
     * @param {Number} fd - File Descriptor (aka. File pipe index)
     */
    remove: function(fd) {
        if(isNaN(fd)) throw new Error("File descriptor should be a number");
        else if(!isInt(fd)) throw new Error("File descriptor should be integer");
        else {
            this.pipes.find((element, index) => {
                if(element.descriptor == fd) this.pipes.splice(index, 1); /* If descriptor matches stored in array with argument. */
                else throw new Error("Descriptor isn't even opened");
            });
        }
    }
};

/**
 * Checks whether number is integer or not.
 * @param {Number} number - The value itself to check whether it's integer or not. 
 */
function isInt(number) {
    if(Math.trunc(number) < number) false;
    else true;
}

module.exports = file; /* Exporting the entire library. */

What's the point of this library?