//箭头函数
const a = (参数列表) => {}
//放入两个或两个以上参数
const sum = (num1, num2) => {
return num1 + num2
}
//放入一个参数
const power = num => {
return num * num
}
//函数代码块中只有一行代码
const mul = (num1, num2) => num1 * num2
const obj = {
fn() {
setTimeout(function() {
console.log(this); //window
setTimeout( () => {
console.log(this); //window
}, 1000)
}, 1000)
setTimeout( () => {
console.log(this); //obj
setTimeout( () => {
console.log(this); //obj
}, 1000)
}, 1000)
}
}
obj.fn();