键值对列表转换为一个对象，与 Object.entries() 相对的（互逆）

const entries = new Map([
  ['key1', 'value1'],
  ['key2', 'value2'],
])

const obj = Object.fromEntries(entries)

console.log(obj) // { key1: 'value1', key2: 'value2' }

Map 转化为 Object

const map = new Map([
  ['foo', 'bar'],
  ['baz', 42],
])

// const map = new Map();
// map.set('key1','value1')
// map.set('key2','value2')

const obj = Object.fromEntries(map)
console.log(obj) // { key1: 'value1', key2: 'value2' }

Array 转化为 Object

const arr = [
  ['0', 'a'],
  ['1', 'b'],
  ['2', 'c'],
]
const obj = Object.fromEntries(arr)
console.log(obj) // { 0: 'a', 1: 'b', 2: 'c' }

对象转换

const course = {
  abc: 1,
  def: 2,
  ghksks: 3,
}

const res = Object.fromEntries(
  Object.entries(course).filter(([key, val]) => key.length === 3)
)
console.log(res)