js闭包的使用场景

function createCounter() {
    let count = 0; // 私有变量
    return {
        increment: function() {
            count++;
            return count;
        },
        decrement: function() {
            count--;
            return count;
        }
    };
}

const counter = createCounter();
console.log(counter.increment()); // 1
console.log(counter.increment()); // 2
console.log(counter.decrement()); // 1

function greetAfterDelay(delayInSeconds, message) {
    setTimeout(function() {
        console.log(message);
    }, delayInSeconds * 1000);
}

greetAfterDelay(2, "Hello, World!"); // 2秒后输出 "Hello, World!"

const Module = (function() {
    let privateVariable = "I am private";

    function privateMethod() {
        console.log(privateVariable);
    }

    return {
        publicMethod: function() {
            privateMethod();
        }
    };
})();

Module.publicMethod(); // 输出 "I am private"

function curry(fn) {
    const args = Array.prototype.slice.call(arguments, 1);
    return function() {
        const innerArgs = Array.prototype.slice.call(arguments);
        const finalArgs = args.concat(innerArgs);
        return fn.apply(null, finalArgs);
    };
}

function add(a, b) {
    return a + b;
}

const curriedAdd = curry(add, 5);
console.log(curriedAdd(3)); // 输出 8

function memoize(fn) {
    const cache = {};
    return function(arg) {
        if (cache[arg] !== undefined) {
            return cache[arg];
        }
        const result = fn(arg);
        cache[arg] = result;
        return result;
    };
}

function fibonacci(n) {
    if (n <= 1) return n;
    return fibonacci(n - 1) + fibonacci(n - 2);
}

const memoizedFibonacci = memoize(fibonacci);
console.log(memoizedFibonacci(10)); // 输出 55