Reading, Writing, and Deleting Files

All five languages have high-level APIs for creating, reading, and deleting files without managing file descriptors by hand. Node.js uses Promise-based functions in node:fs/promises; Go returns (value, error) directly — no exceptions, just an err you check right after each call; Rust also returns a Result, but uses ? to propagate the error instead of checking it manually; Swift and Java use exceptions (throws/try) like JavaScript, just stricter about error types.

Creating, writing, reading, and deleting a file

import { readFile, unlink, writeFile } from 'node:fs/promises'
 
// create file (and write to it)
await writeFile('test.txt', 'hello world.')
 
// read file
const contents = await readFile('test.txt', 'utf8')
console.log(contents)
 
// delete file
await unlink('test.txt')

package main
 
import (
	"fmt"
	"os"
)
 
func main() {
	// create file (and write to it)
	if err := os.WriteFile("test.txt", []byte("hello world."), 0644); err != nil {
		panic(err)
	}
 
	// read file
	contents, err := os.ReadFile("test.txt")
	if err != nil {
		panic(err)
	}
 
	fmt.Println(string(contents))
 
	// delete file
	if err := os.Remove("test.txt"); err != nil {
		panic(err)
	}
}

use std::fs;
 
fn main() -> std::io::Result<()> {
    // create file (and write to it)
    fs::write("test.txt", "hello world.")?;
 
    // read file
    let contents = fs::read_to_string("test.txt")?;
    println!("{contents}");
 
    // delete file
    fs::remove_file("test.txt")?;
 
    Ok(())
}

import Foundation
 
// create file (and write to it)
try "hello world.".write(toFile: "test.txt", atomically: true, encoding: .utf8)
 
// read file
let contents = try String(contentsOfFile: "test.txt", encoding: .utf8)
print(contents)
 
// delete file
try FileManager.default.removeItem(atPath: "test.txt")

void main() throws Exception {
    Path path = Path.of("test.txt");
 
    // create file (and write to it)
    Files.writeString(path, "hello world.");
 
    // read file
    String contents = Files.readString(path);
    IO.println(contents);
 
    // delete file
    Files.delete(path);
}

hello world.