Question

我怎样才能每分钟发出10条承诺？

我在列表中有这些动态日期：

var dates = ["2016-08-31T23:00:00.000Z","2016-09-01T23:00:00.000Z","2016-09-02T23:00:00.000Z","2016-09-03T23:00:00.000Z","2016-09-04T23:00:00.000Z","2016-09-05T23:00:00.000Z","2016-09-06T23:00:00.000Z","2016-09-07T23:00:00.000Z","2016-09-08T23:00:00.000Z","2016-09-09T23:00:00.000Z","2016-09-10T23:00:00.000Z","2016-09-11T23:00:00.000Z","2016-09-12T23:00:00.000Z","2016-09-13T23:00:00.000Z","2016-09-14T23:00:00.000Z","2016-09-15T23:00:00.000Z","2016-09-16T23:00:00.000Z","2016-09-17T23:00:00.000Z","2016-09-18T23:00:00.000Z","2016-09-19T23:00:00.000Z","2016-09-20T23:00:00.000Z","2016-09-21T23:00:00.000Z","2016-09-22T23:00:00.000Z","2016-09-23T23:00:00.000Z","2016-09-24T23:00:00.000Z","2016-09-25T23:00:00.000Z","2016-09-26T23:00:00.000Z","2016-09-27T23:00:00.000Z","2016-09-28T23:00:00.000Z","2016-09-29T23:00:00.000Z","2016-09-30T23:00:00.000Z","2016-10-01T23:00:00.000Z"];

我想获取与这些日期相关的内容或结果。但是我不想一气呵成，但是每分钟都要记下10件，直到日期不复存在。

这是我的工作代码：

     var promises = dates.map(function (date, i) {
        return getContent(date);
    });

    Promise.all(promises).then((data) => {
        console.log(data);
    }).catch((err) => {
        console.log(err.message);
    });

它连续获取内容，而不是我想要的内容。

但是有可能实现我的需要吗？有什么想法吗？

备注：

getContent(date)包含大量的async await承诺，因此调用它的promse.all也必须是promise，否则我可以获得所有返回数据当承诺结束时，在一个地方（console.log(data);）。

修改

const delayValue = (val, ms) => {
    new Promise(resolve => {
        setTimeout(resolve.bind(null, val), ms)
    });
}

Answer 1

如果您坚持使用promises，请使用设置的超时解析器创建一个承诺。

在内部弹出数组并做任何你喜欢的事情。承诺所有这些承诺都会成为我认为的伎俩。

但为什么要承诺而不是设置超时的简单for循环？

Answer 2

Promise只会解析一次，所以如果你需要每分钟都有结果，和想用promises做这件事，你需要为每个数据块分别做一个承诺。

以下是通过使用自定义delayValue函数重复创建承诺来实现此目的的方法：

＆＃13;

const delayValue = (val, ms) => 
    new Promise(resolve => setTimeout(resolve.bind(null, val), ms));

async function loopDates(dates, chunk, delay) {
    for (let i = 0; i < dates.length; i += chunk) {
        console.log(await delayValue(dates.slice(i, i+chunk), i ? delay : 0));
    }
}

var dates = ["2016-08-31T23:00:00.000Z", "2016-09-01T23:00:00.000Z", "2016-09-02T23:00:00.000Z", "2016-09-03T23:00:00.000Z", "2016-09-04T23:00:00.000Z", "2016-09-05T23:00:00.000Z", "2016-09-06T23:00:00.000Z", "2016-09-07T23:00:00.000Z", "2016-09-08T23:00:00.000Z", "2016-09-09T23:00:00.000Z", "2016-09-10T23:00:00.000Z", "2016-09-11T23:00:00.000Z", "2016-09-12T23:00:00.000Z", "2016-09-13T23:00:00.000Z", "2016-09-14T23:00:00.000Z", "2016-09-15T23:00:00.000Z", "2016-09-16T23:00:00.000Z", "2016-09-17T23:00:00.000Z", "2016-09-18T23:00:00.000Z", "2016-09-19T23:00:00.000Z", "2016-09-20T23:00:00.000Z", "2016-09-21T23:00:00.000Z", "2016-09-22T23:00:00.000Z", "2016-09-23T23:00:00.000Z", "2016-09-24T23:00:00.000Z", "2016-09-25T23:00:00.000Z", "2016-09-26T23:00:00.000Z", "2016-09-27T23:00:00.000Z", "2016-09-28T23:00:00.000Z", "2016-09-29T23:00:00.000Z", "2016-09-30T23:00:00.000Z", "2016-10-01T23:00:00.000Z"];

loopDates(dates, 10, 2000);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

现在要将getContent因素添加到其中，您可以像执行map一样（虽然可以缩短语法），然后在每个块上应用Promise.all：< / p>

＆＃13;

const delayValue = (val, ms) => 
    new Promise(resolve => setTimeout(resolve.bind(null, val), ms));

// Mock for getContent:
const getContent = date => Promise.resolve(date);
    
async function loopDates(dates, chunk, delay) {
    const promises = dates.map(getContent);
    
    for (let i = 0; i < dates.length; i += chunk) {
        console.log(await delayValue(Promise.all(promises.slice(i, i+chunk)), 
                                     i ? delay : 0));
    }
}

var dates = ["2016-08-31T23:00:00.000Z", "2016-09-01T23:00:00.000Z", "2016-09-02T23:00:00.000Z", "2016-09-03T23:00:00.000Z", "2016-09-04T23:00:00.000Z", "2016-09-05T23:00:00.000Z", "2016-09-06T23:00:00.000Z", "2016-09-07T23:00:00.000Z", "2016-09-08T23:00:00.000Z", "2016-09-09T23:00:00.000Z", "2016-09-10T23:00:00.000Z", "2016-09-11T23:00:00.000Z", "2016-09-12T23:00:00.000Z", "2016-09-13T23:00:00.000Z", "2016-09-14T23:00:00.000Z", "2016-09-15T23:00:00.000Z", "2016-09-16T23:00:00.000Z", "2016-09-17T23:00:00.000Z", "2016-09-18T23:00:00.000Z", "2016-09-19T23:00:00.000Z", "2016-09-20T23:00:00.000Z", "2016-09-21T23:00:00.000Z", "2016-09-22T23:00:00.000Z", "2016-09-23T23:00:00.000Z", "2016-09-24T23:00:00.000Z", "2016-09-25T23:00:00.000Z", "2016-09-26T23:00:00.000Z", "2016-09-27T23:00:00.000Z", "2016-09-28T23:00:00.000Z", "2016-09-29T23:00:00.000Z", "2016-09-30T23:00:00.000Z", "2016-10-01T23:00:00.000Z"];

loopDates(dates, 10, 2000);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

JavaScript - 每分钟发送10个承诺？

2 个答案: