博客

看完下面的题，你确定你能对几个，得到结果并且说明原因。下一篇有回复

提醒：题目很虐心 

===========================ES6 START======================
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;
})();




===========================ES6 END========================
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.
);