JavaScript 虐心题集

Question

提醒：题目很虐心

1.

(function(x, f = () => x) {
  var x;
  var y = x;
  x = 2;
  return [x, y, f()];
})(1)

2.

(function() {
  return [
    (() => this.x).bind({ x: 'inner' })(),
    (() => this.x)()
  ]
}).call({ x: 'outer' });

3.

let x, { x: y = 1 } = { x }; y;

4.

(function() {
  let f = this ? class g { } : class h { };
  return [
    typeof f,
    typeof h
  ];
})();

5.

(typeof (new (class { class () {} })))

6.

typeof (new (class F extends (String, Array) { })).substring

7.

[...[...'...']].length

8.

typeof (function* f() { yield f })().next().next()

9.

typeof (new class f() { [f]() { }, f: { } })[`${f}`]

10.

typeof `${{Object}}`.prototype

11.

((...x, xs)=>x)(1,2,3)

12.

let arr = [ ];
for (let { x = 2, y } of [{ x: 1 }, 2, { y }]) {
  arr.push(x, y);
}
arr;u

13.

(function() {
  if (false) {
    let f = { g() => 1 };
  }
  return typeof f;
})();

1

(function(){ 
  return typeof arguments; 
})();

2

var f = function g(){ return 23; }; 
typeof g();

3

(function(x){ 
  delete x; 
  return x; 
})(1);

4

var y = 1, x = y = typeof x;
x;

5

(function f(f){
    return typeof f();
  })(function(){ return 1; });

6

var foo = {
    bar: function() { return this.baz; },
    baz: 1
  };
  (function(){
    return typeof arguments[0]();
  })(foo.bar);

7

var foo = {
    bar: function(){ return this.baz; },
    baz: 1
  }
  typeof (f = foo.bar)();

8

var f = (function f(){ return "1"; }, function g(){ return 2; })();
  typeof f;

9

var x = 1;
if (function f(){}) {
x += typeof f;
}
x;

10

var x = [typeof x, typeof y][1];
  typeof typeof x;

11

(function(foo){
    return typeof foo.bar;
  })({ foo: { bar: 1 } });

12

(function f(){
    function f(){ return 1; }
    return f();
    function f(){ return 2; }
  })();

13

function f(){ return f; }
  new f() instanceof f;

14

with (function(x, undefined){}) length;

15

typeof typeof(null)

16

100['toString']['length']

17

var a = (1,5 - 1) * 2

18

var x = 10;
var foo = {
    x: 20,
    bar: function () {
        var x = 30;
        return this.x;
    }
};

console.log(
	foo.bar(),             // 1.
	(foo.bar)(),           // 2.
	(foo.bar = foo.bar)(), // 3.
	(foo.bar, foo.bar)()   // 4.
);