A more accessible API wrapper over Node's builtin `fs.stat`.

check-file.ts

/*
 * Created by Trevor Sears <trevor@trevorsears.com> (https://trevorsears.com/).
 * 2:49 PM -- July 18th, 2022
 */

import fs from "fs";
import process from "node:process";

export type CheckFileOptions = {
	isFile?: boolean,
	isDirectory?: boolean,
	isReadable?: boolean,
	isWriteable?: boolean,
	isExecutable?: boolean,
};

export async function checkFile(filePath: string,
								options?: CheckFileOptions): Promise<boolean> {
	
	let stats: fs.Stats;
	
	try {
		
		stats = await fs.promises.stat(filePath);
		
	} catch (error: any) {
		
		if (error?.code === "ENOENT") return false;
		else throw error;
		
	}
	
	if (options?.isFile === true && !stats.isFile()) return false;
	
	if (options?.isDirectory === true && !stats.isDirectory()) return false;
	
	if (options?.isReadable === true) {
		
		const readableByAll: boolean =
			(stats.mode & fs.constants.S_IROTH) === fs.constants.S_IROTH;
		
		const readableByGroup: boolean = (
			((stats.mode & fs.constants.S_IRGRP) === fs.constants.S_IRGRP) &&
			(process.getegid !== undefined) &&
			(stats.gid === process.getegid())
		);
		
		const readableByUser: boolean = (
			((stats.mode & fs.constants.S_IRUSR) === fs.constants.S_IRUSR) &&
			(process.geteuid !== undefined) &&
			(stats.uid === process.geteuid())
		);
		
		if (!readableByAll && !readableByGroup && !readableByUser) {
			
			return false;
			
		}
		
	}
	
	if (options?.isWriteable === true) {
		
		const writeableByAll: boolean =
			(stats.mode & fs.constants.S_IWOTH) === fs.constants.S_IWOTH;
		
		const writeableByGroup: boolean = (
			((stats.mode & fs.constants.S_IWGRP) === fs.constants.S_IWGRP) &&
			(process.getegid !== undefined) &&
			(stats.gid === process.getegid())
		);
		
		const writeableByUser: boolean = (
			((stats.mode & fs.constants.S_IWUSR) === fs.constants.S_IWUSR) &&
			(process.geteuid !== undefined) &&
			(stats.uid === process.geteuid())
		);
		
		if (!writeableByAll && !writeableByGroup && !writeableByUser) {
			
			return false;
			
		}
		
	}
	
	if (options?.isExecutable === true) {
		
		const executableByAll: boolean =
			(stats.mode & fs.constants.S_IXOTH) === fs.constants.S_IXOTH;
		
		const executableByGroup: boolean = (
			((stats.mode & fs.constants.S_IXGRP) === fs.constants.S_IXGRP) &&
			(process.getegid !== undefined) &&
			(stats.gid === process.getegid())
		);
		
		const executableByUser: boolean = (
			((stats.mode & fs.constants.S_IXUSR) === fs.constants.S_IXUSR) &&
			(process.geteuid !== undefined) &&
			(stats.uid === process.geteuid())
		);
		
		if (!executableByAll && !executableByGroup && !executableByUser) {
			
			return false;
			
		}
		
	}
	
	return true;
	
}