为什么在这个生成器函数中给水果分配了“苹果”？ [复制]

Question

标题说明了一切。

输出是：

starting
lol
undefined
0 undefined

预期：

starting // yield giving us back a string
lol  // yield giving back result from bar()
'apples' // since the 'yield bar()' is 'replaced' by 'apples' via next('apples')
'0 apples' // the last yield should tell us what fruit is, but its undefined

代码：

const bar = () => 'lol'

function* foo1() {
  yield 'starting'
  let a = 0
  let fruit = yield bar()
  console.log(fruit) // <-- y no apples? I could even see 'lol' being here too.
  yield `${a} ${fruit}`

}

let g = foo1()

console.log(g.next().value)
console.log(g.next('apples').value)
console.log(g.next().value)

Answer 1

根据Mozilla Docs功能*

//next的第一次调用从函数开始执行到第一个yield语句

在获得 yield 语句之前，您必须先调用 next() 'init'

const bar = () => 'lol'

function* foo1() {  
  yield 'starting'
  let a = 0
  let fruit = yield bar()
  console.log(fruit)  // <-- y no apples? I could even see 'lol' being here too.
  yield `${a} ${fruit}`
  
}

let g = foo1()
g.next();
console.log( g.next().value)
console.log( g.next('apples').value )