当我定义和描述对象卡车的方法时,为什么我的程序不工作。驱动器()

我对下面的代码有疑问,它会抛出一个类似语法错误的错误,但我遵循的指南说语法是正确的。不知道该怎么办,不明白,请帮忙。

以下是代码链接:

const car = {
    maker: 'Ford',
    model: 'Fiesta',
  
    drive() {
      console.log(`Driving a ${this.maker} ${this.model} car!`)
    }
  }

car.drive()

// the same above code can be written as:
const bus = {
    maker: 'Ford',
    model: 'Bussie',
  
    drive: function() {
      console.log(`Driving a ${this.maker} ${this.model} bus!`)
    }
  }

bus.drive()

// the same code above can be written in this way:
const truck = {
    maker: 'Tata',
    model: 'Truckie',
  
    truck.drive = function() {
      console.log(`Driving a ${this.maker} ${this.model} truck!`)
    }
  }

truck.drive()

// Now, let us see how the arror function works:
const bike = {
    maker: 'Honda',
    model: 'Unicorn',
  
    drive: () => {
      console.log(`Driving a ${this.maker} ${this.model} bike!`)
    }
  }
  
bike.drive()

错误:

SyntaxError: Unexpected token '.'

at line: truck.drive = function() {