js this return

console.log(this); // 在浏览器中输出: Window {...}

const obj = {
  name: 'Alice',
  greet: function() {
    console.log(`Hello, my name is ${this.name}`);
  }
};

obj.greet(); // 输出: Hello, my name is Alice

function showThis() {
  console.log(this);
}

showThis(); // 在浏览器中非严格模式下输出: Window {...}，严格模式下输出: undefined

function showThis() {
  console.log(this);
}

const obj = { name: 'Bob' };

showThis.call(obj); // 输出: { name: 'Bob' }
showThis.apply(obj); // 输出: { name: 'Bob' }

const boundShowThis = showThis.bind(obj);
boundShowThis(); // 输出: { name: 'Bob' }

const obj = {
  name: 'Charlie',
  greet: function() {
    setTimeout(() => {
      console.log(`Hello, my name is ${this.name}`);
    }, 100);
  }
};

obj.greet(); // 输出: Hello, my name is Charlie

function Person(name) {
  this.name = name;
}

const alice = new Person('Alice');
console.log(alice.name); // 输出: Alice

const calculator = {
  value: 0,
  add: function(num) {
    this.value += num;
    return this;
  },
  subtract: function(num) {
    this.value -= num;
    return this;
  },
  getValue: function() {
    return this.value;
  }
};

calculator.add(5).subtract(2).getValue(); // 输出: 3