js call apply bind区别

// 使用 call 方法
function greet(name, age) {
  console.log(`Hello, my name is ${name} and I am ${age} years old. This function was called by ${this.name}.`);
}

const obj = { name: 'Alice' };

greet.call(obj, 'Bob', 30); 
// 输出: Hello, my name is Bob and I am 30 years old. This function was called by Alice.

// 使用 apply 方法
function greetWithApply(name, age) {
  console.log(`Hello, my name is ${name} and I am ${age} years old. This function was called by ${this.name}.`);
}

greetWithApply.apply(obj, ['Charlie', 25]);
// 输出: Hello, my name is Charlie and I am 25 years old. This function was called by Alice.

// 使用 bind 方法
function greetWithBind(name, age) {
  console.log(`Hello, my name is ${name} and I am ${age} years old. This function was called by ${this.name}.`);
}

const boundGreet = greetWithBind.bind(obj, 'David', 35);
boundGreet(); 
// 输出: Hello, my name is David and I am 35 years old. This function was called by Alice.

解释说明：

• call 方法：立即调用函数，并将指定的对象作为 this 上下文传递给函数，同时可以传递参数列表。
• apply 方法：与 call 类似，但参数是以数组的形式传递。
• bind 方法：创建一个新的函数，并将指定的对象作为 this 上下文绑定到该新函数上。新函数可以在稍后的时间点被调用。

以上代码展示了如何使用 call、apply 和 bind 来改变函数的 this 上下文并传递参数。