对象的扩展

module.exports = { getItem, setItem, clear };
 
// 等同于
module.exports = {
  getItem: getItem,
  setItem: setItem,
  clear: clear
};

var o = {
  method() {
    return "Hello!";
  }
};
// 等同于
var o = {
  method: function() {
    return "Hello!";
  }
};

let propKey = ‘foo‘;
let obj = {
  [propKey]: true,
  [‘a‘ + ‘bc‘]: 123
};

Object.is(‘foo‘, ‘foo‘)
// true
Object.is({}, {})
// false

var target = { a: 1 };
var source1 = { b: 2 };
var source2 = { c: 3 };
Object.assign(target, source1, source2);
target // {a:1, b:2, c:3}

var obj1 = {a: {b: 1}};
var obj2 = Object.assign({}, obj1);
obj1.a.b = 2;
obj2.a.b // 2

class Point {
  constructor(x, y) {
    Object.assign(this, {x, y});
  }
}

const merge =
  (target, ...sources) => Object.assign(target, ...sources);

const DEFAULTS = {
     logLevel: 0,
     outputFormat: ‘html‘
};
function processContent(options) {
     options = Object.assign({}, DEFAULTS, options);
     console.log(options);
  // ...
}

let z = { a: 3, b: 4 };
let n = { ...z };
n // { a: 3, b: 4 }