来自函数嵌套的Javascript生成器发生器 [英] Javascript yield from the function nested inside generator

问题描述

此代码产生错误：

function *giveNumbers() {
    [1, 2, 3].forEach(function(item) {
        yield item;
    })
}

这可能是因为yield不在生成器的函数内。有没有一个优雅的方式来克服这个？我的意思是：

This is probably because yield is inside a function that is not a generator. Is there an elegant way to overcome this? I mean other than:

function *giveNumbers() {
    let list = [1, 2, 3];
    for (let i = 0; i < list.length; i++) {
        yield list[i];
    }
}

推荐答案

这可能是因为yield不在生成器的函数内。

This is probably because yield is inside a function that is not a generator.

是的。您不能从回调中使用 yield 。

Yes. You cannot use yield from callbacks.

有没有一个优雅的方式来克服这个？

Is there an elegant way to overcome this?

取决于用例。通常没有理由要从回调中实际想要 yield 。

Depends on the use case. Usually there is zero reason to actually want to yield from a callback.

在你的情况下，你想要一个 for ... of 循环，在 .forEach q / 31344516/1048572>几乎每个方面反正：

In your case, you want a for…of loop, which is superior to .forEach in almost every aspect anyway:

function *giveNumbers() {
    for (let item of [1, 2, 3])
        yield item;
}

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