Object.defineProperty

Object.defineProperty

var foo = {}
Object.defineProperty(foo, 'name', {
  configurable: true, //是否可以delete foo.delete
  enumerable: true, // 是否for in可以返回属性
  writable:true, //是否可以重新赋值
  value: 'kobe'
})

var descriptor = Object.getOwnPropertyDescriptor(foo, 'name')
console.log(descriptor.value)
console.log(foo.name) // kobe

function sum(list) {
  if (list.length === 0) {
    return 0;
  } else {
    const [atom, ...remainder] = list;
    const left = atom;
    const right = sum(remainder);

    return left + right;
  }
}

sum([42, 3, -1])