如何访问setTimeout内部产生的值? [英] How can I access the value yielded from inside a setTimeout?

问题描述

我有此代码:

function* showValue() {
  setTimeout(function*() {
    console.log('yielding')
    return yield 100;
  }, 1000);
}

var valFunc = showValue();
console.log(valFunc.next());

运行它时，我看到以下输出:

When I run it, I see this output:

{ value: undefined, done: true }

为什么要让 .next()调用返回100?

Why should I do to have the .next() call return 100?

推荐答案

您可能会考虑如下更改代码；

You might think about changing the code as follows;

function showValue() {
    return setTimeout(function() {
        function* gen() {
            console.log('yielding');
            yield 100;
        };
        var it = gen();
        console.log(it.next().value);
    }, 1000);
}
showValue();              // will display result after 1000+ms
console.log(showValue()); // will immediately display setTimeout id and after 1000+ms will display the generator yielded value again.

这篇关于如何访问setTimeout内部产生的值?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！