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Output 输出类

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类型转换类​

'true' == true 
'false' == false
null == ''
['x'] == 'x'
[1, 2, 3] == [1, 2, 3]
true + false
[1] > null
"foo" + + "bar"
0 || "0" && {}
{} + [] + {} + [1]
! + [] + [] + ![]
new Date(0) - 0
new Date(0) + 0
'ca' < 'bd'
Boolean(new Boolean(false))

this 类​

var a = 10
var obj = {
  a: 20,
  say: () => {
    console.log(this.a)
  }
}
obj.say()

var anotherObj = {
  a: 30
}
obj.say.apply(anotherObj)
var obj = {
  say: function () {
    var f1 = () => {
      console.log("1111", this);
    }
    f1();
  },
  pro: {
    getPro: () => {
      console.log(this);
    }
  }
}
var o = obj.say;

o();
obj.say();
obj.pro.getPro();
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);
    }());
  }
};
myObject.func();
var a = 1;
function printA() {
  console.log(this.a);
}
var obj = {
  a: 2,
  foo: printA,
  bar: function () {
    printA();
  }
}

obj.foo();
obj.bar();

var foo = obj.foo;
foo();
var x = 3;
var y = 4;
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())
console.log(obj.getY())

作用域类​

(function(){
   var x = y = 1;
})();
var z;

console.log(y);
console.log(z);
console.log(x);
// a
function Foo() {
  getName = function () {
    console.log(1);
  }
  return this;
}
// b
Foo.getName = function () {
  console.log(2);
}
// c
Foo.prototype.getName = function () {
  console.log(3);
}
// d
var getName = function () {
  console.log(4);
}
// e
function getName() {
  console.log(5);
}

Foo.getName();
getName();
Foo().getName();
getName();
new Foo.getName();
new Foo().getName();
new new Foo().getName();

setTimeout 类 + 怎么解决​

for (var i = 0; i < 5; i++) {
  setTimeout(() => {
    console.log(i)
  }, i * 1000)
}

Promise 类​

const promise = new Promise((resolve, reject) => {
  console.log(1);
  console.log(2);
});
promise.then(() => {
  console.log(3);
});
console.log(4);
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);
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');
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);
})
Promise.resolve('1')
  .then(res => {
    console.log(res)
  })
  .finally(() => {
    console.log('finally1')
  })
Promise.resolve('2')
  .finally(() => {
    console.log('finally2')
    return '我是finally2返回的值'
  })
  .then(res => {
    console.log(res)
  })
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)
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');
});
setTimeout(function () {
  console.log(1);
}, 100);

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

Async / Await 类​

async function async1() {
  console.log("async1 start");
  await async2();
  console.log("async1 end");
}
async function async2() {
  console.log("async2");
}
async1();
console.log('start')
async function async1() {
  console.log('async1 start');
  await new Promise(resolve => {
    console.log('promise1')
  })
  console.log('async1 success');
  return 'async1 end'
}
console.log('srcipt start')
async1().then(res => console.log(res))
console.log('srcipt end')
async function async1() {
  console.log('async1 start');
  await new Promise(resolve => {
    console.log('promise1')
    resolve('promise1 resolve')
  }).then(res => console.log(res))
  console.log('async1 success');
  return 'async1 end'
}
console.log('srcipt start')
async1().then(res => console.log(res))
console.log('srcipt end')
async function async1() {
  console.log("async1 start");
  await async2();
  console.log("async1 end");
}

async function async2() {
  console.log("async2");
}

console.log("script start");

setTimeout(function () {
  console.log("setTimeout");
}, 0);

async1();

new Promise(resolve => {
  console.log("promise1");
  resolve();
}).then(function () {
  console.log("promise2");
});
console.log('script end')

process.nextTick 类​

console.log('1');

setTimeout(function () {
  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(function () {
  console.log('9');
  process.nextTick(function () {
    console.log('10');
  })
  new Promise(function (resolve) {
    console.log('11');
    resolve();
  }).then(function () {
    console.log('12')
  })
})