js-arrow

var a = {
b: function() {
console.log(this)
},
c: () => console.log(this),
d() {
console.log(this)
},
e() {
return new Promise(
() => console.log(this)
)
},
f: function() {
return new Promise(
() => console.log(this)
)
},
g: function() {
return new Promise(
() => console.log(this.axios)
)
},

        i() {
            return () => (
                console.log(this.axios)

            )

        },
        h() {
            return () => ({
                i() {
                    console.log(this.axios)
                }
            })
        },
        o() {
            return () => {
                return () => {
                    console.log(this.axios)
                }
            }
        },
        p() {
            return () => {
                return () => ({
                    i() {
                        console.log(this.axios)
                    }
                })
            }
        },
        u: () => ({
            i() {
                console.log(this.axios)
            }
        }),
        y: () => ({
            i: () => (console.log(this))
        }),
    }
    // es6 浏览器隐式调用 strict mode。u内部所在作用于是window但箭头函数内的i的调用caller和argument受到限制，所以返回underfined
a.axios = 1;
axios = "";