const names = ['abc', 'cba', 'nba', NaN];
// ES5
if(names.indexOf('cba') !== -1) {
  console.log('包含cba');
}
// ES7
if(names.includes('cba', 2)) { // fromIndex
  console.log('包含cba');
}
// indexOf无法判断NaN
if(names.indexOf(NaN) !== -1) {
  console.log('包含NaN');
}
// includes可以判断NaN
if(names.includes(NaN)) {
  console.log('包含NaN');
}

var name = 'zjf';
var age = 21;

var obj = {
  // 1.property shorthand(属性的简写)
  name,
  age,

  // 2.method shorthand
  foo: function() {
    console.log(this);
  },
  bar() {
    console.log(this);
  },
  baz:() => {
    console.log(this);
  },

  // 3.computed property name(计算属性名)
  [name + 123]: 'hahaha'
}

obj.foo();
obj.bar();
obj.baz();
console.log(obj);