代码之家 › 专栏 › 技术社区 › Deepak Dev

如何在包含多个异步函数的foreach循环中返回数据

async-await node.js

Deepak Dev · 技术社区 · 2 年前

我使用wait调用这个函数,并将数据存储在结果变量中。但是函数返回时没有完成foreach循环。只有foreach循环结束时,我怎样才能使这个函数返回?

let result = await prepareStocks(data);

async function prepareStocks(incomingStocks) { 
    var stockCodes = incomingStocks.stocks.split(',');
    var stockPrices = incomingStocks.trigger_prices.split(',');
    var alertName = incomingStocks.alert_name;
    stockCodes.forEach(async(stocks, index) => {

        if (stockPrices[index] > 100) {

            var stockCodes = {
                code: stocks,
                price: stockPrices[index],
                orderType: (urls.buy.includes(alertName) ? 'BUY' : 'WATCH'),
                target: await setSellPrice(stockPrices[index], 1),
                stopLoss: await setStopLoss(stockPrices[index], 1),
            }
            STOCKS.push(stockCodes);
        }

    });
    return STOCKS;

}

1 回复 | 直到 2 年前

Brijesh Patel 2 年前

尝试使用 Promise.all

类似这样的东西=>

let result = await prepareStocks(data);
async function prepareStocks(incomingStocks) { 
    var stockCodes = incomingStocks.stocks.split(',');
    var stockPrices = incomingStocks.trigger_prices.split(',');
    var alertName = incomingStocks.alert_name;


    const STOCKS = await Promise.all(stockCodes.map(async (stocks, index) => {
        if (stockPrices[index] > 100) {

            var stockCodes = {
                code: stocks,
                price: stockPrices[index],
                orderType: (urls.buy.includes(alertName) ? 'BUY' : 'WATCH'),
                target: await setSellPrice(stockPrices[index], 1),
                stopLoss: await setStopLoss(stockPrices[index], 1),
            }
            return stockCodes;
        }
    })

    return STOCKS;
}

Tamil Vendhan Kanagarasu 2 年前

在阅读了async/await部分之后,我想知道async/await的使用方式没有问题; STOCKS 必须返回预期值。因此,我设置了一个如下的模拟&运行代码。

async function setSellPrice(price) { return new Promise(function resolver(resolve) {setTimeout(function someTimeLater() { resolve(price)});}); }
async function setStopLoss(price) { return new Promise(function resolver(resolve) {setTimeout(function someTimeLater() { resolve(price)});}); }
const data = { stocks: 'A,B,C'. trigger_prices: '100,120,140', alert_name: 'XYZ' };
let result = await prepareStocks(data);

而且 股票 未定义错误。

你的代码是正确的 async/await 作品原始代码的问题是 股票 变量未定义。我想,它在其他任何地方都没有定义。所以,按照预期做以下工作。

let result = await prepareStocks(data);

async function prepareStocks(incomingStocks) { 
    const STOCKS = [];
    var stockCodes = incomingStocks.stocks.split(',');
    var stockPrices = incomingStocks.trigger_prices.split(',');
    var alertName = incomingStocks.alert_name;
    stockCodes.forEach(async(stocks, index) => {

        if (stockPrices[index] > 100) {

            var stockCodes = {
                code: stocks,
                price: stockPrices[index],
                orderType: (urls.buy.includes(alertName) ? 'BUY' : 'WATCH'),
                target: await setSellPrice(stockPrices[index], 1),
                stopLoss: await setStopLoss(stockPrices[index], 1),
            }
            STOCKS.push(stockCodes);
        }

    });
    return STOCKS;

}