ES6 javascript中class静态方法、属性与实例属性用法示例

class Foo {
  static classMethod() {
    return 'hello';
  }
}
Foo.classMethod() // 'hello'
var foo = new Foo();
foo.classMethod()
// TypeError: foo.classMethod is not a function

class Foo {
  static classMethod() {
    return 'hello';
  }
}
class Bar extends Foo {}
Bar.classMethod(); // 'hello'

class Foo {
  static classMethod() {
    return 'hello';
  }
}
class Bar extends Foo {
  static classMethod() {
    return super.classMethod() + ', too';
  }
}
Bar.classMethod();

class Foo {}
Foo.prop = 1;
Foo.prop // 1

// 以下两种写法都无效
class Foo {
  // 写法一
  prop: 2
    // 写法二
  static prop: 2
}
Foo.prop // undefined

class MyClass {
  myProp = 42;
  constructor() {
    console.log(this.myProp); // 42
  }
}

class ReactCounter extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }
}

class ReactCounter extends React.Component {
  state = {
    count: 0
  };
}

class ReactCounter extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }
  state;
}

class MyClass {
static myStaticProp = 42;
constructor() {
console.log(MyClass.myProp); // 42
}
}

// 老写法
class Foo {}
Foo.prop = 1;
// 新写法
class Foo {
  static prop = 1;
}