js手写代码题汇总

this相关的题

1. 题1

function Test1() {
	function foo() {
		console.log(this.a);
		console.log(a); // 2
	}
	function doFoo() {
		console.log(this.a)
		foo();
	}
	var obj = {
		a: 1,
		doFoo,
	};
	var a = 2;
	obj.doFoo();
}
Test1()

// 1
// undefined
// 2

2. 题2

箭头函数本身没有this，在箭头函数中访问this取决于词法作用域定义下的上下文中的this

function Test2() {
	var obj = {
		a: 20,
		say: () => {
			console.log(this.a);
		},
	};
	obj.say();
	var anotherObj = { a: 30 };
	obj.say.apply(anotherObj);
}
Test2()
// undefined
// undefined

3. 题3

function Test3() {
	function a() {
		console.log(this);
	}
	a.call(null);
}
Test3()
// Window or global

4. 题4

function Test4() {
	var obj = {
		name: "abin",
		func: function () {
			console.log(this.name);
		},
	};
	obj.func();
	new obj.func();
}
Test4()

// abin
// undefined

5. 题5

function Test5() {
	var obj = {
		say: function () {
			var f1 = () => {
				console.log(this);
			};
			f1();
		},
		pro: {
			getPro: () => {
				console.log(this);
			},
		},
	};
	var o = obj.say;
	o(); // o在全局执行，父级say的this指向全局作用域
	obj.say(); // obj.say执行时，say的this指向obj，箭头函数使用父级的this
	obj.pro.getPro(); // 对象不构成作用域，箭头函数的this指向了全局作用域
}
Test5()

// Window
// obj
// Window

6. 题6

function Test6() {
	var myObject = {
		foo: "bar",
		func: function () {
			var self = this;
			console.log(this.foo);
			console.log(self.foo);
			(function () {
				console.log(this.foo);
				console.log(self.foo);
			})(); // 立即执行函数的this指向window
		},
	};
	myObject.func();
}
Test6()

// bar
// bar
// undefined
// bar

7. 题7

function Test7() {
	window.number = 2;
	var obj = {
		number: 3,
		db1: (function () {
			console.log(this);
			this.number *= 4;
			return function () {
				console.log(this);
				this.number *= 5;
			};
		})(),
	};
	var db1 = obj.db1;
	db1();
	obj.db1();
	console.log(obj.number);
	console.log(window.number);
}
Test7()

// Window
// Window
// obj
// 15
// 40

8. 题8

function Test8() {
	function fn() {
		console.log(this.length); // 这里两个参数，所以长度为2
	}
	var obj = {
		length: 5,
		method: function (fn) {
			fn(); // this指向window
			arguments[0]();  // this指向arguments
		},
	};
	obj.method(fn, 1);
}
Test8()

// undefined
// 2

9. 题9

function Test9() {
	var a = 1;
	function printA() {
		console.log(this.a);
	}
	var obj = {
		a: 2,
		foo: printA,
		bar: function () {
			printA();
		},
	};
	obj.foo();  // this指向对象
	obj.bar(); // printA的this指向了window
	var foo = obj.foo; 
	foo();
}
Test9()

// 2
// undefined
// undefined

10. 题10

var x = 3;
var y = 4;
// 题10
function Test10() {
	var obj = {
		x: 1,
		y: 6,
		getX: function () {
			var x = 5;
			return (function () {
				return this.x;
			})();
		},
		getY: function () {
			var y = 7;
			return this.y;
		},
	};
	console.log(obj.getX()); // this指向了window
	console.log(obj.getY());
}
Test10()

// 3
// 6

11. 题11

var a = 10;
function Test11() {
	var obj = {
		a: 20,
		fn: function () {
			var a = 30;
			console.log(this.a);
		},
	};
	obj.fn();
	obj.fn.call(); // call没有指定参数，this指向window
	(obj.fn)(); // 括号表示优先级不影响结果
}
Test11();

// 20
// 10
// 20

12. 题12

function Test12() {
	function foo(something) {
		this.a = something
	}
	var obj1 = {
		foo
	}

	var obj2 = {}

	obj1.foo(2)
	console.log(obj1.a); // 2
	obj1.foo.call(obj2, 3)
	console.log(obj2.a); //  3

	var bar = new obj1.foo(4)
	console.log(obj1.a); // 2
	console.log(bar.a); // 4
	var bindFn = obj1.foo.bind(obj2)
	bindFn(7)
	var bar2 = new bindFn(8)
	console.log(obj2.a); // 7
	console.log(bar2.a); // 8

}
Test12()

// this绑定的优先级: new绑定 > 显式绑定 > 隐式绑定 > 默认绑定
// 2
// 3
// 2
// 4
// 7
// 8

作用域相关

1. 题1

function Test1() {
	(function () {
		var x = (y = 1); // 从右往左执行，y=1，y为全局变量， x是局部变量
	})();
	var z;
	console.log(y);
	console.log(z);
	console.log(x);
}
Test1()

// 1
// undefined
// Uncaught ReferenceError:x is not defined

2. 题2

function Test2() {
	var a, b;
	(function () {
		console.log(a);
		console.log(b);
		var a = (b = 3);
		console.log(a);
		console.log(b);
	})();
	console.log(a);
	console.log(b);
}
Test2()

// undefined
// undefined
// 3
// 3
// undefined
// 3

3. 题3

function Test3() {
	var friendName = "World";
	(function () {
		if (typeof friendName === "undefined") {
			var friendName = "Jack";  // 此处的var声明，导致变量提升，没有块级作用域
			console.log("Goodbye " + friendName);
		} else {
			console.log("Hello " + friendName);
		}
	})();
	console.log(friendName)
}
Test3();

// Goodbye Jack
// World

4. 题4

function Test4() {
	function fn1() {
		console.log("fn1");
	}
	var fn2; // 函数赋给变量，不会发生函数提升
	fn1();
	fn2();
	fn2 = function () {
		console.log("fn2");
	};
	fn2();
}
Test4()

// fn1
// TypeError: fn2 is not a function

5. 题5

function Test5() {
	function fn1() {
		console.log("fn1");
	}
	fn1();
	fn2();
	function fn2() { // 函数变量提升
		console.log("fn2"); 
	}
	fn2();
}
Test5()

// fn1
// fn2
// fn2

6. 题6

function Test7() {
	window.number = 2;
	var obj = {
		number: 3,
		db1: (function () {
			console.log(this);
			this.number *= 4;
			return function () {
				console.log(this);
				this.number *= 5;
			};
		})(),
	};
	var db1 = obj.db1;
	db1();
	obj.db1();
	console.log(obj.number);
	console.log(window.number);
}
Test7()

// Window
// Window
// obj
// 15
// 40

7. 题7

function Test8() {
	function fun(n, o) {
		console.log(o);
		return {
			fun: function (m) {
				return fun(m, n);
			},
		};
	}
	var a = fun(0);
	a.fun(1);
	a.fun(2);
	a.fun(3);

	var b = fun(0).fun(1).fun(2).fun(3);

	var c = fun(0).fun(1);
	c.fun(2);
	c.fun(3);
}
Test8()

// undefined
// 0
// 0
// 0
// undefined
// 0
// 1
// 2
// undefined
// 0
// 1
// 1

8. 题8

g = function () {
	return false;
};
f = function () {
	return true;
};

function Test9() {
	(function () {
		if (window.g() && [] == ![]) {
			f = function () {
				return false;
			};
			function g() {
				return true;
			}
		}
	})();
	console.log(f());
}
Test9();

// true

原型链相关

1. 题1

function Test1() {
	function Person(name) {
		this.name = name
	}
	var p2 = new Person('king')
	console.log(p2.__proto__); // {constructor: Person}
	console.log(p2.__proto__.__proto__); // Object.prototype
	console.log(p2.__proto__.__proto__.__proto__); // null
	console.log(p2.constructor); // Person
	console.log(p2.prototype); // undefined
	console.log(Person.constructor); // ƒ Function() { [native code] }
	console.log(Person.prototype); // {constructor: Person}
	console.log(Person.prototype.constructor); // Person
	console.log(Person.prototype.__proto__); // Object.prototype
	console.log(Person.__proto__); //  ƒ Function() { [native code] }
	console.log(Function.prototype.__proto__); // Object.prototype
	console.log(Function.__proto__); // ƒ Function() { [native code] }
	console.log(Function.__proto__.__proto); // Object.prototype
	console.log(Object.__proto__); // ƒ Function() { [native code] }
	console.log(Object.prototype.__proto__); // null
}
Test1()

2. 题2

function Foo() {
	getName = function () {
		console.log(1);
	}
	return this
}

Foo.getName = function () {
	console.log(2);
}

Foo.prototype.getName = function () {
	console.log(3);
}
var getName = function () {
	console.log(4);
}

function getName() {
	console.log(5);
}

Foo.getName() // 2
getName() // 4
Foo().getName() // 1
getName() // 1
new Foo.getName() // 2
new Foo().getName() // 3
new new Foo().getName() // 3

3. 题3

function Test3() {
	var F = function () {

	}
	Object.prototype.a = function () {
		console.log('a');
	}
	Function.prototype.b = function () {
		console.log('b');
	}
	var f = new F()
	f.a() // a
	f.b() // Uncaught TypeError: f.b is not a function
	F.a() // a
	F.b() // b
}
Test3()

4. 题4

function Test4() {
    function Foo() {
        Foo.a = function () {
            console.log(1);
        }
        this.a = function () {
            console.log(2);
        }
    }
    Foo.prototype.a = function () {
        console.log(3);
    }
    Foo.a = function () {
        console.log(4);
    }
    Foo.a() // 4
    let obj = new Foo()
    obj.a() // 2
    Foo.a() // 1
}
Test4()

// 4
// 2
// 1

5. 题5

function Test5() {
	function Dog() {
		this.name = 'puppy'
	}
	Dog.prototype.bark = () => {
		console.log('woof!');
	}
	const dog = new Dog()
	console.log(Dog.prototype.constructor === Dog && dog.constructor === Dog && dog instanceof Dog)
}
Test5()

// true

6. 题6

function Test6() {
	var A = { n: 4399 }
	var B = function () {
		this.n = 9999
	}
	var C = function () {
		var n = 8888
	}
	B.prototype = A
	C.prototype = A
	var b = new B()
	var c = new C()
	A.n++
	console.log(b.n); // 9999
	console.log(c.n); // 4400
}
Test6()

// 9999
// 4400

7. 题7

function Test7() {
	function A() {

	}
	function B(a) {
		this.a = a
	}
	function C(a) {
		if (a) {
			this.a = a
		}
	}
	A.prototype.a = 1
	B.prototype.a = 1
	C.prototype.a = 1
	console.log(new A().a); // 1
	console.log(new B().a); // undefined
	console.log(new C(2).a); // 2
}
Test7()

// 1
// undefined
// 2

8. 题8

function Test8() {
	function Parent() {
		this.a = 1
		this.b = [1, 2, this.a]
		this.c = { demo: 5 }
		this.show = function () {
			console.log(this.a, this.b, this.c.demo);
		}
	}
	function Child() {
		this.a = 2
		this.change = function () {
			this.b.push(this.a)
			this.a = this.b.length
			this.c.demo = this.a++
			console.log('this.c.demo', this.c.demo)
		}
	}
	Child.prototype = new Parent
	var parent = new Parent
	var child1 = new Child
	var child2 = new Child
	child1.a = 11
	child2.a = 12
	parent.show() // 1 [1,2,1] 5
	child1.show() // 11 [1,2,1] 5
	child2.show() // 12 [1,2,1] 5
	child1.change() //this.c.demo  4
	child2.change() //this.c.demo  5
	parent.show() // 1 [1,2,1] 5
	child1.show() // 5 [1,2,1,11,12] 5
	child2.show() // 6 [1,2,1,11,12] 5
}
Test8()

// 1 [ 1, 2, 1 ] 5
// 11 [ 1, 2, 1 ] 5
// 12 [ 1, 2, 1 ] 5
// this.c.demo 4
// this.c.demo 5
// 1 [ 1, 2, 1 ] 5
// 5 [ 1, 2, 1, 11, 12 ] 5
// 6 [ 1, 2, 1, 11, 12 ] 5

9. 题9

function Test9() {
	function SuperType() {
		this.property = true
	}
	SuperType.prototype.getSuperValue = function () {
		return this.property
	}
	function SubType() {
		// this.subproperty = false
		this.property = 'aaa'
	}
	SubType.prototype = new SuperType
	SubType.prototype.getSubValue = function () {
		return this.subproperty
	}
	var instance = new SubType
	console.log(instance.getSuperValue());
}
Test9()

// aaa

异步相关

题1

//  prmise.then是微任务，在所有宏任务执行完之后才会执行， 因为promise一直pending，所以不输出3
function Test1() {
	const promise = new Promise((resolve, reject) => {
		console.log(1);
		console.log(2);
	});

	promise.then(() => {
		console.log(3);
	});
	console.log(4);
}
Test1()
// 1
// 2
// 4

题2

function Test2() {
	const promise1 = new Promise((resolve, rejct) => {
		console.log('promise1');
		resolve('resolve1');
	});

	const promise2 = promise1.then((res) => {
		console.log(res);
	});
	console.log('1', promise1);
	console.log('2', promise2);
	setTimeout(() => {
		console.log('1', promise1);
		console.log('2', promise2);
	}, 0);
}
Test2()

// promise1
// 1 Promise { 'resolve1' }
// 2 Promise { <pending> }
// resolve1
// 1 Promise { 'resolve1' }
// 2 Promise { undefined }

题3

function Test3() {
	const promise = new Promise((resolve, reject) => {
		console.log(1);
		setTimeout(() => {
			console.log('timerStart');
			resolve('success');
			console.log('timerEnd');
		}, 0);
		console.log(2);
	});
	promise.then((res) => {
		console.log(res);
	});
	console.log(4);
}
Test3()

// 1
// 2
// 4
// timerStart
// timerEnd
// success

题4

function Test4() {
	Promise.resolve().then(() => {
		console.log('promise1');
		const timer2 = setTimeout(() => {
			console.log('timer2');
		}, 0);
	});
	const timer1 = setTimeout(() => {
		console.log('timer1');
		Promise.resolve().then(() => {
			console.log('promise2');
		});
	}, 0);
	console.log('start');
}
Test4()

// start
// promise1
// timer1
// promise2
// timer2

题5

function Test5() {
	const promise = new Promise((resolve, reject) => {
		resolve('success1');
		reject('error');
		resolve('success2');
	});
	promise
		.then((res) => {
			console.log('then:', res);
		})
		.catch((err) => {
			console.log('catch:', err);
		});
}
Test5()

// then: success1

题6

Promise.resolve自动为原始值返回新的Promise对象

then方法接收的参数是函数，如果传入的不是函数，则将其解释为then(null)

function Test6() {
	Promise.resolve(1).then(2).then(console.log);
}
Test6();

// 1

题7

在node中
promise1 Promise { <pending> }
promise2 Promise { <pending> }
Error: error!!!

在浏览器中
promise1 Promise { <pending> }
promise2 Promise { <pending> }
Error: error!!!
promise1 Promise {<fulfilled>: 'success'}
Promise2 {<rejected>: Error: error!!! ...}

题8

then的回调会返回一个新的promise，从而实现了链式调用

function Test8() {
	Promise.resolve(1)
		.then((res) => {
			console.log(res);
			return 2;
		})
		.catch((err) => {
			return 3;
		})
		.then((res) => {
			console.log(res);
		});
}
Test8()

// 1
// 2

题9

function Test9() {
	Promise.resolve()
		.then(() => {
			return new Error('error!!!');
		})
		.then((res) => {
			console.log('then:', res);
		})
		.catch((err) => {
			console.log('catch:', err);
		});
}
Test9()

// then: Error: error!!!

题10

function Test10() {
	const promise = Promise.resolve().then(() => {
		return promise;
	});
	promise.catch(console.err);
}
// Test10()
// 结果： Uncaught (in promise) TypeError: Chaining cycle detected for promise #<Promise>
// 解析，then或者catch不能返回promise本身，否则会造成死循环

题11

function Test11() {
    // 错误被then的第二个参数捕获了，所以就不能被catch了
	Promise.reject('err!!!')
		.then(
			(res) => {
				console.log('success', res);
			},
			(err) => {
				console.log('error', err);
			}
		)
		.catch((err) => {
			console.log('catch', err);
		});
}
Test11()

// error err!!!

题12

finally方法不论Promise最终何种状态都会执行，finally不接受任何参数，它最终返回的是上一个promise的值，如果抛出异常则返回异常的promise对象

function Test12() {
	Promise.resolve('1')
		.then((res) => {
			console.log(res);
		})
		.finally(() => {
			console.log('finally');
		});

	Promise.resolve('2')
		.finally(() => {
			console.log('finally2');
			return '我是finally2返回的值';
		})
		.then((res) => {
			console.log('finally2后面的then函数', res);
		});
}
Test12();

// 1
// finally2
// finally
// finally2后面的then函数 2

题13

function Test13() {
	function runAsync(x) {
		const p = new Promise((r) =>
			setTimeout(() => {
				r(x, console.log(x));
			}, 1000)
		);
		return p;
	}
	Promise.all([runAsync(1), runAsync(2), runAsync(3)]).then((res) => console.log(res));
}
Test13();

// 1
// 2
// 3
// [ 1, 2, 3 ]

题14

如果一组异步操作中有一个异常都不会进入.then的第一个回调函数，会被第二个回调捕获

function Test14() {
	function runAsync(x) {
		const p = new Promise((r) =>
			setTimeout(() => {
				r(x, console.log(x));
			}, 1000)
		);
		return p;
	}
	function runReject(x) {
		const p = new Promise((res, rej) =>
			setTimeout(() => {
				rej(`Error:${x}`, console.log(x));
			}, 1000 * x)
		);
		return p;
	}
	Promise.all([runAsync(1), runReject(4), runAsync(3), runReject(2)])
		.then((res) => console.log(res))
		.catch((err) => console.log(err));
}
Test14();

// 1
// 3
// 2
// Error:2
// 4

题15

then只会捕获第一个成功的方法，其他的函数虽然继续执行，但是不被then捕获了

function Test15() {
	function runAsync(x) {
		const p = new Promise((r) =>
			setTimeout(() => {
				r(x, console.log(x));
			}, 1000)
		);
		return p;
	}
	Promise.race([runAsync(1), runAsync(2), runAsync(3)])
		.then((res) => console.log('result:', res))
		.catch((err) => console.log(err));
}
Test15();

// 1
// result: 1
// 2
// 3

题16

Promise完成后，后续抛出的错误将不会再捕获

function Test16() {
	function runAsync(x) {
		const p = new Promise((r) =>
			setTimeout(() => {
				r(x, console.log(x));
			}, 1000)
		);
		return p;
	}
	function runReject(x) {
		const p = new Promise((res, rej) =>
			setTimeout(() => {
				rej(`Error:${x}`, console.log(x));
			}, 1000 * x)
		);
		return p;
	}
	Promise.race([runAsync(0), runReject(1), runAsync(2), runReject(3)])
		.then((res) => console.log(res))
		.catch((err) => console.log(err));
}
Test16()

// 0
// 0
// 1
// 2
// 3

题17

await后的语句相当于放在Promise.then中

function Test17() {
	async function async1() {
		console.log('async1 start');
		await async2();
		console.log('async1 end');
	}
	async function async2() {
		console.log('async2');
	}
	async1();
	console.log('start');
}
Test17()

// async1 start
// async2
// start
// async1 end

题18

function Test18() {
	async function async1() {
		console.log('async1 start');
		await async2();
		console.log('async1 end');
		setTimeout(() => {
			console.log('timer1');
		}, 0);
	}
	async function async2() {
		setTimeout(() => {
			console.log('timer2');
		}, 0);
		console.log('async2');
	}
	async1();
	setTimeout(() => {
		console.log('timer3');
	}, 0);
	console.log('start');
}
Test18()

// async1 start
// async2
// start
// async1 end
// timer2
// timer3
// timer1

题19

Promise一直pending所以await后面的内容不会执行，包括async1的then中

function Test19() {
	async function async1() {
		console.log('async1 start');
		await new Promise((resolve) => {
			console.log('promise1');
		});
		console.log('async1 success');
		return 'async1 end';
	}
	console.log('script start');
	async1().then((res) => console.log(res));
	console.log('script end');
}
Test19()

// script start
// async1 start
// promise1
// script end

题20

function Test20() {
	async function async1() {
		console.log('async1 start');
		await async2();
		console.log('async1 end');
	}
	async function async2() {
		console.log('async2');
	}
	console.log('script start');
	setTimeout(() => {
		console.log('setTimeout');
	}, 0);
	async1();
	new Promise((resolve) => {
		console.log('promise1');
		resolve();
	}).then(function() {
		console.log('promise2');
	});
	console.log('script end');
}
Test20()

// script start
// async1 start
// async2
// promise1
// script end
// async1 end
// promise2
// setTimeout

题21

async函数抛出错误，不会继续往下执行，可以用catch捕获错误

function Test21() {
	async function async1() {
		await async2();
		console.log('async1');
		return 'async1 success';
	}
	async function async2() {
		return new Promise((resolve, reject) => {
			console.log('async2');
			reject('error');
		});
	}
	async1().then((res) => console.log(res));
}
Test21()

// async2
// Uncaught (in promise) error

题22

Promise一直pending所以await后面的内容不会执行，包括async1的then中

function Test22() {
	async function async1() {
		console.log('async1 start');
		await new Promise((resolve) => {
			console.log('promise1');
		});
		console.log('async1 success');
		return 'async1 end';
	}
	console.log('script start');
	async1().then((res) => console.log(res));
	console.log('script end');
}
Test22()

// script start
// async1 start
// promise1
// script end

题23

async函数抛出错误，不会继续往下执行，可以用catch捕获错误

function Test23() {
	async function async1() {
		await async2().catch((e) => console.log(e));
		console.log('async1');
		return 'async1 success';
	}
	async function async2() {
		return new Promise((resolve, reject) => {
			console.log('async2');
			reject('error');
		});
	}
	async1().then((res) => console.log(res));
}
Test23()

// async2
// error
// async1
// async1 success

题24

Promise中 resolve之后的代码也会执行的

function Test24() {
	const first = () =>
		new Promise((resolve, reject) => {
			console.log(3);
			let p = new Promise((resolve, reject) => {
				console.log(7);
				setTimeout(() => {
					console.log(5);
					resolve(6);
					console.log(p);
				}, 0);
				resolve(1);
			});
			resolve(2);
			p.then((arg) => {
				console.log(arg);
			});
		});
	first().then((arg) => {
		console.log(arg);
	});
	console.log(4);
}
Test24()

// 3
// 7
// 4
// 1
// 2
// 5
// Promise {1}

题25

function Test25() {
	const async1 = async () => {
		console.log('async1');
		setTimeout(() => {
			console.log('timer1');
		}, 2000);
		await new Promise((resolve) => {
			console.log('promise1');
		});
		console.log('async1 end');
		return 'async1 success';
	};
	console.log('script start');
	async1().then((res) => console.log(res));
	console.log('script end');
	Promise.resolve(1).then(2).then(Promise.resolve(3)).catch(4).then((res) => console.log(res));
	setTimeout(() => {
		console.log('timer2');
	}, 1000);
}
Test25();

// script start
// async1
// promise1
// script end
// 1
// timer2
// timer1

题26

function Test26() {
	const p1 = new Promise((resolve) => {
		setTimeout(() => {
			resolve('resolve3');
			console.log('timer1');
		}, 0);
		resolve('resolve1');
		resolve('resolve2');
	})
		.then((res) => {
			console.log(res);
			setTimeout(() => {
				// 如果这个then不返回值，那么p1的Promise值最终为undefined
				console.log(p1);
			}, 1000);
			// return res
		})
		.finally((res) => {
			console.log('finally', res);
		});
}
Test26()

// resolve1
// finally undefined
// timer1
// Promise <fulfilled undefined>

题27

function Test27() {
	console.log(1);
	setTimeout(() => {
		console.log(2);
		process.nextTick(function () {
			console.log(3);
		});
		new Promise(function (resolve) {
			console.log(4);
			resolve();
		}).then(function () {
			console.log(5);
		});
	});
	process.nextTick(function () {
		console.log(6);
	});
	new Promise(function (resolve) {
		console.log(7);
		resolve();
	}).then(function () {
		console.log(8);
	});
	setTimeout(() => {
		console.log(9);
		process.nextTick(function () {
			console.log(10);
		});
		new Promise(function (resolve) {
			console.log(11);
			resolve();
		}).then(function () {
			console.log(12);
		});
	});
}
Test27();

// 1
// 7
// 6
// 8
// 2
// 4
// 3
// 5
// 9
// 11
// 10
// 12

题28

function Test28() {
	console.log(1);
	setTimeout(() => {
		console.log(2);
	});
	new Promise((resolve) => {
		console.log(3);
		resolve(4);
	}).then((d) => console.log(d));

	setTimeout(() => {
		console.log(5);
		new Promise((resolve) => {
			resolve(6);
		}).then((d) => console.log(d));
	});

	setTimeout(() => {
		console.log(7);
	});
	console.log(8);
}
Test28();

// 1
// 3
// 8
// 4
// 2
// 5
// 6
// 7

题29

function Test29() {
	console.log(1);
	setTimeout(() => {
		console.log(2);
		Promise.resolve().then(() => {
			console.log(3);
		});
	});

	new Promise((resolve, reject) => {
		console.log(4);
		resolve(5);
	}).then((data) => {
		console.log(data);
	});

	setTimeout(() => {
		console.log(6);
	});
	console.log(7);
}
Test29();

// 1
// 4
// 7
// 5
// 2
// 3
// 6

题30

function Test30() {
	Promise.resolve()
		.then(() => {
			console.log(1);
			throw 'Error';
		})
		.then(() => {
			console.log(2);
		})
		.catch(() => {
			console.log(3);
			throw 'Error';
		})
		.then(() => {
			console.log(4);
		})
		.catch(() => {
			console.log(5);
		})
		.then(() => {
			console.log(6);
		});
}
Test30();

// 1
// 3
// 5
// 6

题31

function Test31() {
	setTimeout(() => {
		console.log(1);
	}, 100);
	new Promise(function (resolve) {
		console.log(2);
		resolve()
		console.log(3);
	}).then(function () {
		console.log(4);
		new Promise((resolve, reject) => {
			console.log(5);
			setTimeout(() => {
				console.log(6);
			}, 10);
		})
	})
	console.log(7);
	console.log(8);
}
Test31()

// 2
// 3
// 7
// 8
// 4
// 5
// 6
// 1