1. 分析输出

for (var i = 0; i < 3; i++) {
    setTimeout(() => console.log(i), 1)
}

for (let i = 0; i < 3; i++) {
    setTimeout(() => console.log(i), 1)
}

2. 分析输出

const shape = {
    radius: 10,
    diameter() {
        return this.radius * 2
    },
    perimeter: () => 2 * Math.PI * this.radius,
}

shape.diameter()
shape.perimeter()

3. 分析输出

const a = {}

function test1(a) {
    a = {
        name: 'wdd',
    }
}

function test2() {
    test1(a)
}

function test3() {
    console.log(a)
}

test2()
test3()

4. 分析输出

class Chameleon {
    static colorChange(newColor) {
        this.newColor = newColor
        return this.newColor
    }

    constructor({ newColor = 'green' } = {}) {
        this.newColor = newColor
    }
}

const freddie = new Chameleon({ newColor: 'purple' })
freddie.colorChange('orange')

5. 分析输出

function Person(firstName, lastName) {
    this.firstName = firstName
    this.lastName = lastName
}

const member = new Person('Lydia', 'Hallie')
Person.getFullName = function () {
    return `${this.firstName} ${this.lastName}`
}

console.log(member.getFullName())

6. 事件传播的三个阶段是什么？

  • A: Target > Capturing > Bubbling
  • B: Bubbling > Target > Capturing
  • C: Target > Bubbling > Capturing
  • D: Capturing > Target > Bubbling

7. 所有对象都有原型

A: 对 B: 错

8. 输出？

function sum(a, b) {
    return a + b
}

sum(1, '2')

9. 输出？

function getPersonInfo(one, two, three) {
    console.log(one)
    console.log(two)
    console.log(three)
}

const person = 'Lydia'
const age = 21

getPersonInfo`${person} is ${age} years old`

输出？

function checkAge(data) {
    if (data === { age: 18 }) {
        console.log('You are an adult!')
    } else if (data == { age: 18 }) {
        console.log('You are still an adult.')
    } else {
        console.log(`Hmm.. You don't have an age I guess`)
    }
}

checkAge({ age: 18 })

输出？

function getAge(...args) {
    console.log(typeof args)
}

getAge(21)